C++
Divide-Conquer[71% passed]
1 class Solution { 2 public: 3 /** 4 * @param nums: a list of integers 5 * @return: A integer denote the sum of minimum subarray 6 */ 7 int minSubArray(vector<int> nums) { 8 // write your code here 9 int n = nums.size(); 10 if (n == 1) { 11 return nums[0]; 12 } 13 int *arr = nums.data(); 14 return helper(arr, n); 15 } 16 int helper(int *arr, int n) { 17 // terminate 18 if ( n == 1 ) { 19 return arr[0]; 20 } 21 // divide 22 int mid = n>>1; 23 int ans = min(helper(arr, mid), helper(arr + mid, n - mid)); 24 // conquer 25 int now = arr[mid - 1], may = now; 26 for (int i = mid-2; i >= 0; --i) { 27 may = min(may, now += arr[i]); 28 } 29 now = may; 30 for (int i = mid; i <= n; ++i) { 31 may = min(may, now += arr[i]); 32 } 33 // return 34 return min(may, ans); 35 } 36 };
C++, dp
1 class Solution { 2 public: 3 /** 4 * @param nums: a list of integers 5 * @return: A integer denote the sum of minimum subarray 6 */ 7 int minSubArray(vector<int> nums) { 8 // write your code here 9 int n = nums.size(); 10 if (n == 1) { 11 return nums[0]; 12 } 13 vector<int> dp(n); 14 dp[0] = nums[0]; 15 int ans = nums[0]; 16 for (int i = 1; i < n ; ++i) { 17 dp[i] = min(nums[i], dp[i - 1]+nums[i]); 18 ans = min(dp[i], ans); 19 } 20 return ans; 21 } 22 };
C++,dp,O(1) space
1 class Solution { 2 public: 3 /** 4 * @param nums: a list of integers 5 * @return: A integer denote the sum of minimum subarray 6 */ 7 int minSubArray(vector<int> nums) { 8 // write your code here 9 int n = nums.size(); 10 if (n == 1) { 11 return nums[0]; 12 } 13 int endHere = nums[0]; 14 int ans = nums[0]; 15 for (int i = 1; i < n ; ++i) { 16 endHere = min(nums[i], endHere+nums[i]); 17 ans = min(endHere, ans); 18 } 19 return ans; 20 } 21 };