From befb6879d60f30208d5de85c859f1e6c6c195b8a Mon Sep 17 00:00:00 2001 From: LSGOMYP Date: Mon, 14 Sep 2020 16:36:04 +0800 Subject: [PATCH] =?UTF-8?q?=E8=AF=BE=E7=A8=8B=E5=86=85=E5=AE=B9=E6=9B=B4?= =?UTF-8?q?=E6=96=B0?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../05 Leetcode同步练习（一）.md | 791 ++++++++++++++++++ .../{05 数组.md => 06 数组.md} | 0 ...{06 顺序表和链表.md => 07 顺序表和链表.md} | 0 .../{07 栈与递归.md => 09 栈与递归.md} | 0 .../{09 字符串.md => 10 字符串.md} | 0 5 files changed, 791 insertions(+) create mode 100644 DataStructureAndAlgorithm/05 Leetcode同步练习（一）.md rename DataStructureAndAlgorithm/{05 数组.md => 06 数组.md} (100%) rename DataStructureAndAlgorithm/{06 顺序表和链表.md => 07 顺序表和链表.md} (100%) rename DataStructureAndAlgorithm/{07 栈与递归.md => 09 栈与递归.md} (100%) rename DataStructureAndAlgorithm/{09 字符串.md => 10 字符串.md} (100%) diff --git a/DataStructureAndAlgorithm/05 Leetcode同步练习（一）.md b/DataStructureAndAlgorithm/05 Leetcode同步练习（一）.md new file mode 100644 index 0000000..561b9dc --- /dev/null +++ b/DataStructureAndAlgorithm/05 Leetcode同步练习（一）.md @@ -0,0 +1,791 @@ + +# Leetcodeͬϰһ + +## Ŀ01֮ + +> - ţ1 +> - Ѷȣ +> - https://leetcode-cn.com/problems/two-sum/ + +һ `nums` һĿֵ `target`ڸҳΪĿֵ ǵ±ꡣ + +ԼÿֻӦһ𰸡ǣ㲻ظͬԪء + +**ʾ1:** + +```c + nums = [2, 7, 11, 15], target = 9 + +Ϊ nums[0] + nums[1] = 2 + 7 = 9Է [0, 1] +``` + +**ʾ2** + +```c + nums = [230, 863, 916, 585, 981, 404, 316, 785, 88, 12, 70, 435, 384, 778, 887, 755, 740, 337, 86, 92, 325, 422, 815, 650, 920, 125, 277, 336, 221, 847, 168, 23, 677, 61, 400, 136, 874, 363, 394, 199, 863, 997, 794, 587, 124, 321, 212, 957, 764, 173, 314, 422, 927, 783, 930, 282, 306, 506, 44, 926, 691, 568, 68, 730, 933, 737, 531, 180, 414, 751, 28, 546, 60, 371, 493, 370, 527, 387, 43, 541, 13, 457, 328, 227, 652, 365, 430, 803, 59, 858, 538, 427, 583, 368, 375, 173, 809, 896, 370, 789], target = 542 + +Ϊ nums[28] + nums[45] = 221 + 321 = 542Է [28, 45] +``` + +**ο룺** + +˼·ֱñƥ㷨 + +- ִнͨ +- ִʱ432 ms, C# ύл 65.82% û +- ڴģ30.8 MB, C# ύл 8.67% û + +```c +public class Solution +{ + public int[] TwoSum(int[] nums, int target) + { + int[] result = new int[2]; + for (int i = 0; i < nums.Length - 1; i++) + { + int find = target - nums[i]; + for (int j = i + 1; j < nums.Length; j++) + { + if (find == nums[j]) + { + result[0] = i; + result[1] = j; + return result; + } + } + } + return result; + } +} +``` + + +--- +## Ŀ02ɾеظ + +> - ţ26 +> - Ѷȣ +> - https://leetcode-cn.com/problems/remove-duplicates-from-sorted-array/ + +һ ****Ҫ **ԭ** ɾظֵԪأʹÿԪֻһΣƳ³ȡ + +Ҫʹöռ䣬 **ԭ޸** ʹ O(1) ռɡ + +ʾ 1: + +```c + nums = [1,1,2], +Ӧ÷µij 2, ԭ nums ǰԪر޸Ϊ 1, 2 +㲻Ҫг³ȺԪء +``` + +ʾ 2: + +```c + nums = [0,0,1,1,1,2,2,3,3,4], +Ӧ÷µij 5, ԭ nums ǰԪر޸Ϊ 0, 1, 2, 3, 4 +㲻Ҫг³ȺԪء +``` + +˵: + +ΪʲôֵĴ? + +ע⣬ԡ****ʽݵģζں޸ڵǿɼġ + +ڲ: + +```c +// nums ԡáʽݵġҲ˵ʵκο +int len = removeDuplicates(nums); + +// ں޸ڵǿɼġ +// ĺصij, ӡиóȷΧڵԪء +for (int i = 0; i < len; i++) { + print(nums[i]); +} +``` + + + +**ο룺** + +˼·˫һһ`j``i``nums[j] == nums[i]`ʱ`j++`Ϳظʱ`i++``nums[i] = nums[j]`ֵƹִеĩβɣʱ临ӶΪ`O(n)` + +- ִнͨ +- ִʱ300 ms, C# ύл 64.43% û +- ڴģ33.5 MB, C# ύл 5.48% û + +```c +public class Solution +{ + public int RemoveDuplicates(int[] nums) + { + if (nums.Length < 2) + return nums.Length; + + int i = 0; + for (int j = 1; j < nums.Length; j++) + { + if (nums[j] != nums[i]) + { + i++; + nums[i] = nums[j]; + } + } + return i + 1; + } +} +``` + +--- +## Ŀ03ƳԪ + +> - ţ27 +> - Ѷȣ +> - https://leetcode-cn.com/problems/remove-element/ + + +һ`nums`һֵ`val`Ҫ**ԭ**Ƴֵ`val`ԪأƳ³ȡ + +Ҫʹöռ䣬**ԭ޸**ʹ O(1) ռɡ + +Ԫص˳Ըı䡣㲻Ҫг³ȺԪء + +**ʾ 1:** + +```c + nums = [3,2,2,3], val = 3, + +Ӧ÷µij 2, nums еǰԪؾΪ 2 + +㲻Ҫг³ȺԪء +``` + +**ʾ 2:** + +```c + nums = [0,1,2,2,3,0,4,2], val = 2, + +Ӧ÷µij 5, nums еǰԪΪ 0, 1, 3, 0, 4 + +עԪؿΪ˳ + +㲻Ҫг³ȺԪء +``` + +**ʾ 3:** +```c +룺[] value = 0 + +0 +``` + +**ʾ 4:** +```c +룺[1] value = 1 + +0 +``` + +**ʾ 5:** + +```c +룺[4,5] value = 5 + +1 +``` + + + +**˵:** + +ΪʲôֵĴ? + +ע⣬ԡ****ʽݵģζں޸ڵǿɼġ + +ڲ: + +```c +// nums ԡáʽݵġҲ˵ʵκο +int len = removeElement(nums, val); + +// ں޸ڵǿɼġ +// ĺصij, ӡиóȷΧڵԪء +for (int i = 0; i < len; i++) { + print(nums[i]); +} +``` + +**ο룺** + +˼·˫˫`i``j``i`ΪϺ`j`Ϊǰ塣`nums[j]!=val``num[j]`ֵ`num[i]`ѭ`i`ָǰԪأΪҪԪأӶﵽƳԪصĿģʱ临ӶΪ `O(n)` + +- ִнͨ +- ִʱ272 ms, C# ύл 94.41% û +- ڴģ29.9 MB, C# ύл 5.21% û + +```c +public class Solution +{ + public int RemoveElement(int[] nums, int val) + { + int i = 0; + for (int j = 0; j < nums.Length; j++) + { + if (nums[j] != val) + { + nums[i] = nums[j]; + i++; + } + } + return i; + } +} +``` + + +--- +## Ŀ04 + +> - ţ53 +> - Ѷȣ +> - https://leetcode-cn.com/problems/maximum-subarray/ + +һ`nums`ҵһ͵飨ٰһԪأ͡ + +ʾ 1: +```c +: [-2,1,-3,4,-1,2,1,-5,4], +: 6 +: [4,-1,2,1] ĺΪ 6 +``` + +ʾ 2: +```c +: [-2,1], +: 1 +``` + +: + +ѾʵָӶΪ`O(n)`ĽⷨʹøΪķη⡣ + +**ο룺** + +˼·ñ㷨 + +- ״̬ͨ +- ִʱ: 596 ms, C# ύл 14.18% û +- ڴ: 24.5 MB, C# ύл 5.88% û + +```c +public class Solution { + public int MaxSubArray(int[] nums) { + int len = nums.Length; + if (len == 0) + return 0; + if (len == 1) + return nums[0]; + int max = int.MinValue; + + for (int i = 0; i < len; i++) + { + int sum = nums[i]; + if (sum > max) + { + max = sum; + } + for (int j = i + 1; j < len; j++) + { + sum += nums[j]; + if (sum > max) + { + max = sum; + } + } + } + return max; + } +} +``` + +--- +## Ŀ05ʢˮ + + +> - ţ11 +> - Ѷȣе +> - https://leetcode-cn.com/problems/container-with-most-water/ + +`n`Ǹ`a1a2...an`ÿеһ`(i, ai)`ڻ`n`ֱߣֱ`i` ˵ֱΪ`(i, ai)``(i, 0)`ҳеߣʹ`x`Ṳͬɵˮ + +˵㲻б`n`ֵΪ 2 + +![](https://imgconvert.csdnimg.cn/aHR0cHM6Ly9hbGl5dW4tbGMtdXBsb2FkLm9zcy1jbi1oYW5nemhvdS5hbGl5dW5jcy5jb20vYWxpeXVuLWxjLXVwbG9hZC91cGxvYWRzLzIwMTgvMDcvMjUvcXVlc3Rpb25fMTEuanBn?x-oss-process=image/format,png) + +ͼдֱߴ [1,8,6,2,5,4,8,3,7]ڴ£ܹˮʾΪɫֵ֣Ϊ 49 + +ʾ: +```c +: [1,8,6,2,5,4,8,3,7] +: 49 +``` + + +**ο룺** + +˼·˫ķ + +![](https://imgconvert.csdnimg.cn/aHR0cHM6Ly9waWMubGVldGNvZGUtY24uY29tLzg4NGQ1YmNlOTU1ZThiYzA1MGY2NTUxNTQwNGEwNDI2NGYyYzFmZjgyNzYyMWFiZDcyYjgxNzA5ZmUzNzMyM2YtJUU5JTgxJThEJUU1JThFJTg2JUU3JTlBJTg0JUU2JTgzJTg1JUU1JTg2JUI1LmpwZw?x-oss-process=image/format,png) + +0-7ߵ1-7һΪΪʲô0-6һ֧ + +```c +h(i)ʾi߶εĸ߶ȣS(ij)ʾi߶κ͵j߶Ȧ + +֪ h(0) < h(7)ӶS(07) = h(0) * 7 + +S(06) = min(h(0), h(6)) * 6 + +h(0) <= h(6)S(06) = h(0) * 6 +h(0) > h(6)S(06) = h(6) * 6S(06) < h(0) * 6 + +ɴ˿֪S(06)ȻСS(07) +``` +ÿһͬķ׿֪˫ߵ· + +- ״̬ͨ +- 50 / 50 ͨ +- ִʱ: 144 ms, C# ύл 99.64% û +- ڴ: 26.6 MB, C# ύл 5.45% û + +```c +public class Solution +{ + public int MaxArea(int[] height) + { + int i = 0, j = height.Length - 1; + int max = int.MinValue; + while (i < j) + { + int temp = (j - i) * Math.Min(height[i], height[j]); + if (temp > max) + { + max = temp; + } + if (height[i] < height[j]) + { + i++; + } + else + { + j--; + } + } + return max; + } +} +``` + +--- +## Ŀ06ת + +> - ţ33 +> - Ѷȣе +> - https://leetcode-cn.com/problems/search-in-rotated-sorted-array/ + +谴Ԥδ֪ijϽת + +( 磬 [0,1,2,4,5,6,7] ܱΪ [4,5,6,7,0,1,2] ) + +һĿֵдĿֵ򷵻򷵻 -1 + +ԼвظԪء + +㷨ʱ临Ӷȱ`O(log n)` + +ʾ 1: +```c +: nums = [4,5,6,7,0,1,2], target = 0 +: 4 +``` + +ʾ 2: +```c +: nums = [4,5,6,7,0,1,2], target = 3 +: -1 +``` + +ʾ 3: +```c +: nums = [5,1,3], target = 5 +: 0 +``` + +ʾ 4: +```c +: nums = [4,5,6,7,8,1,2,3], target = 8 +: 4 +``` + +ʾ 5: +```c +: nums = [3,1], target = 1 +: 1 +``` + +**ο룺** + +˼·öַ + +- ״̬ͨ +- ִʱ: 128 ms, C# ύл 97.17% û +- ڴ: 23.8 MB, C# ύл 12.00% û + +```c +public class Solution +{ + public int Search(int[] nums, int target) + { + int i = 0, j = nums.Length - 1; + while (i <= j) + { + int mid = (i + j) / 2; + if (nums[mid] == target) + return mid; + + if (nums[mid] >= nums[i]) + { + //벿 + if (target > nums[mid]) + { + i = mid + 1; + } + else + { + if (target == nums[i]) + return i; + + if (target > nums[i]) + j = mid - 1; + else + i = mid + 1; + } + } + else + { + if (target < nums[mid]) + { + j = mid - 1; + } + else + { + if (target == nums[j]) + return j; + if (target < nums[j]) + i = mid + 1; + else + j = mid - 1; + } + } + } + return -1; + } +} +``` + + + + + +--- +## Ŀ07еĵKԪ + +> - ţ215 +> - Ѷȣе +> - https://leetcode-cn.com/problems/kth-largest-element-in-an-array/ + +δҵ `k` Ԫءע⣬Ҫҵĵ `k` Ԫأǵ `k` ͬԪء + +ʾ 1: +```c +: [3,2,1,5,6,4] k = 2 +: 5 +``` + +ʾ 2: +```c +: [3,2,3,1,2,4,5,5,6] k = 4 +: 4 +``` + +˵: + +Լ `k` Чģ `1 k ij` + + + + + +**ο룺** + +˼·ķ + +- ״̬ͨ +- ִʱ: 152 ms, C# ύл 76.47% û +- ڴ: 24.6 MB, C# ύл 5.55% û + +```c +public class Solution +{ + public int FindKthLargest(int[] nums, int k) + { + nums = nums.OrderBy(a => a).ToArray(); + return nums[nums.Length - k]; + } +} +``` + + + + +--- +## Ŀ08ij˻ + + +> - ţ238 +> - Ѷȣе +> - https://leetcode-cn.com/problems/product-of-array-except-self/ + +Ϊ`n``nums``n > 1``output``output[i]` `nums`г`nums[i]`֮Ԫصij˻ + +ʾ: +```c +: [1,2,3,4] +: [24,12,8,6] +``` + +˵: 벻Ҫʹó`O(n)` ʱ临Ӷɴ⡣ + + + +ڳռ临ӶĿ𣿣 ڶԿռ临ӶȷĿģ鲻Ϊռ䡣 + + + + + + +**ο룺** + +˼·˻ = ǰߵij˻ * ǰұߵij˻ + +```c + [1, 2, 3, 4] + ߵij˻ [1, 1, 2, 6] + ұߵij˻ [24,12,4, 1] + = * [24,12,8, 6] +``` + +- ״̬ͨ +- ִʱ: 304 ms, C# ύл 100.00% û +- ڴ: 34.6 MB, C# ύл 100.00% û + +```c +public class Solution +{ + public int[] ProductExceptSelf(int[] nums) + { + int len = nums.Length; + int[] output1 = new int[len];//˻ + int[] output2 = new int[len];//˻ + output1[0] = 1; + output2[len - 1] = 1; + for (int i = 1; i < len; i++) + { + output1[i] = output1[i - 1]*nums[i - 1]; + output2[len - i - 1] = output2[len - i]*nums[len - i]; + } + for (int i = 0; i < len; i++) + { + output1[i] *= output2[i]; + } + return output1; + } +} +``` + + +--- +## Ŀ09Ѱλ + + +> - ţ4 +> - Ѷȣ +> - https://leetcode-cn.com/problems/median-of-two-sorted-arrays/ + +СΪ`m``n``nums1``nums2` + +ҳλҪ㷨ʱ临ӶΪ`O(log(m + n))` + +Լ`nums1``nums2`ͬʱΪա + +ʾ 1: +```c +nums1 = [1, 3] +nums2 = [2] + +λ 2.0 +``` + +ʾ 2: + +```c +nums1 = [1, 2] +nums2 = [3, 4] + +λ (2 + 3)/2 = 2.5 +``` + +**ο룺** + +˼·öֲԡ + +λһϻΪȵӼһӼеԪǴһӼеԪء + +ĿҪʱ临ӶΪ`O(log(m + n))`ԲܴβҵλӶ `O(m + n)`ҪֲͨԣͨÿαȽϣֱܹӰˢһ֣ҵλӶ`O(log(m + n))` + +```c +nums1: [a1,a2,a3,...am] +nums2: [b1,b2,b3,...bn] + +[nums1[:i],nums2[:j] | nums1[i:], nums2[j:]] + +nums1 ȡ i +nums2 ȡ j = (m+n+1)/2 - i +``` +ֻҪ֤ ͬλ `|` ߽Ա߲Ӷöַҵʵ`i` + +- ״̬ͨ +- ִʱ: 160 ms, C# ύл 99.18% û +- ڴ: 26.8 MB, C# ύл 5.05% û + +```c +public class Solution { + public double FindMedianSortedArrays(int[] nums1, int[] nums2) { + int m = nums1.Length; + int n = nums2.Length; + if (m > n) + return FindMedianSortedArrays(nums2, nums1); + + int k = (m + n + 1)/2; + int left = 0; + int right = m; + while (left < right) + { + int i = (left + right)/2; + int j = k - i; + if (nums1[i] < nums2[j - 1]) + left = i + 1; + else + right = i; + } + int m1 = left; + int m2 = k - left; + int c1 = Math.Max(m1 == 0 ? int.MinValue : nums1[m1 - 1], + m2 == 0 ? int.MinValue : nums2[m2 - 1]); + + if ((m + n)%2 == 1) + return c1; + + int c2 = Math.Min(m1 == m ? int.MaxValue : nums1[m1], + m2 == n ? int.MaxValue : nums2[m2]); + return (c1 + c2)*0.5; + } +} +``` + +--- +## Ŀ10ȱʧĵһ + + +> - ţ41 +> - Ѷȣ +> - https://leetcode-cn.com/problems/first-missing-positive/ + +һδ飬ҳûгֵС + +ʾ1: + +```c +: [1,2,0] +: 3 +``` + +ʾ2: + +```c +: [3,4,-1,1] +: 2 +``` + +ʾ3: +```c +: [7,8,9,11,12] +: 1 +``` + +ʾ4: +```c +: [1,1] +: 2 +``` + +ʵ5: + +```c +: [] +: 1 +``` + +˵: + +㷨ʱ临ӶӦΪO(n)ֻʹóĿռ䡣 + +**ο룺** + +˼·һΡ򡱣򡱵Ĺǣ`i`ڡ䷶Χ`i`Ӧ÷Ϊ`i - 1`λϡ + +- ִнͨ +- ִʱ100 ms, C# ύл 93.75% û +- ڴģ24.2 MB, C# ύл 97.44% û + + +```c +public class Solution { + public int FirstMissingPositive(int[] nums) { + int len = nums.Length; + for (int i = 0; i < len; i++) + { + while (nums[i] != i + 1 && nums[i] <= len && nums[i] > 0 && nums[i] != nums[nums[i] - 1]) + { + int temp = nums[i]; + nums[i] = nums[temp - 1]; + nums[temp - 1] = temp; + } + } + for (int i = 0; i < len; i++) + { + if (nums[i] != i + 1) + { + return i + 1; + } + } + return len + 1; //nums.Length = 0 + } +} +``` + + + diff --git a/DataStructureAndAlgorithm/05 数组.md b/DataStructureAndAlgorithm/06 数组.md similarity index 100% rename from DataStructureAndAlgorithm/05 数组.md rename to DataStructureAndAlgorithm/06 数组.md diff --git a/DataStructureAndAlgorithm/06 顺序表和链表.md b/DataStructureAndAlgorithm/07 顺序表和链表.md similarity index 100% rename from DataStructureAndAlgorithm/06 顺序表和链表.md rename to DataStructureAndAlgorithm/07 顺序表和链表.md diff --git a/DataStructureAndAlgorithm/07 栈与递归.md b/DataStructureAndAlgorithm/09 栈与递归.md similarity index 100% rename from DataStructureAndAlgorithm/07 栈与递归.md rename to DataStructureAndAlgorithm/09 栈与递归.md diff --git a/DataStructureAndAlgorithm/09 字符串.md b/DataStructureAndAlgorithm/10 字符串.md similarity index 100% rename from DataStructureAndAlgorithm/09 字符串.md rename to DataStructureAndAlgorithm/10 字符串.md