1151. Minimum Swaps to Group All 1's Together

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1151. Minimum Swaps to Group All 1’s Together

Description

Given a binary array data, return the minimum number of swaps required to group all 1’s present in the array together in any place in the array.

Example 1:

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Input: data = [1,0,1,0,1]
Output: 1
Explanation: There are 3 ways to group all 1's together:
[1,1,1,0,0] using 1 swap.
[0,1,1,1,0] using 2 swaps.
[0,0,1,1,1] using 1 swap.
The minimum is 1.

Example 2:

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Input: data = [0,0,0,1,0]
Output: 0
Explanation: Since there is only one 1 in the array, no swaps are needed.

Example 3:

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Input: data = [1,0,1,0,1,0,0,1,1,0,1]
Output: 3
Explanation: One possible solution that uses 3 swaps is [0,0,0,0,0,1,1,1,1,1,1].

Constraints:

  • 1 <= data.length <= 10^5
  • data[i] is either 0 or 1.

Hints/Notes

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Solution

Language: C++

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class Solution {
public:
    int minSwaps(vector<int>& data) {
        int n = data.size(), right = 0, k = 0, mx = 0, cur = 0;
        for (int d : data) {
            k += d;
        }
        while (right < n) {
            int r = data[right];
            cur += r;
            if (right >= k - 1) {
                mx = max(mx, cur);
                cur -= data[right - k + 1];
            }
            right++;
        }
        return k - mx;
    }
};