2134. Minimum Swaps to Group All 1's Together II

 JAVA

• class Solution {
      public int minSwaps(int[] nums) {
          int cnt = 0;
          for (int v : nums) {
              cnt += v;
          }
          int n = nums.length;
          int[] s = new int[(n << 1) + 1];
          for (int i = 0; i < (n << 1); ++i) {
              s[i + 1] = s[i] + nums[i % n];
          }
          int mx = 0;
          for (int i = 0; i < (n << 1); ++i) {
              int j = i + cnt - 1;
              if (j < (n << 1)) {
                  mx = Math.max(mx, s[j + 1] - s[i]);
              }
          }
          return cnt - mx;
      }
  }

C++

• class Solution {
  public:
      int minSwaps(vector<int>& nums) {
          int cnt = 0;
          for (int& v : nums) cnt += v;
          int n = nums.size();
          vector<int> s((n << 1) + 1);
          for (int i = 0; i < (n << 1); ++i) s[i + 1] = s[i] + nums[i % n];
          int mx = 0;
          for (int i = 0; i < (n << 1); ++i) {
              int j = i + cnt - 1;
              if (j < (n << 1)) mx = max(mx, s[j + 1] - s[i]);
          }
          return cnt - mx;
      }
  };