# 1769. Minimum Number of Operations to Move All Balls to Each Box
###### tags: `Leetcode` `Medium` `Greedy` `Three Pass`
Link: https://leetcode.com/problems/minimum-number-of-operations-to-move-all-balls-to-each-box/description/
## 思路

## Code

class Solution {
public int[] minOperations(String boxes) {
int n = boxes.length();
int[] leftCnt = new int[n];
int cnt = 0;
for(int i=1; i<n; i++){
cnt += boxes.charAt(i-1)=='1'?1:0;
leftCnt[i] = leftCnt[i-1]+cnt;
}
int[] rightCnt = new int[n];
cnt = 0;
for(int i=n-2; i>=0; i--){
cnt += boxes.charAt(i+1)=='1'?1:0;
rightCnt[i] = rightCnt[i+1]+cnt;
}
int[] ans = new int[n];
for(int i=0; i<n; i++){
ans[i] = leftCnt[i]+rightCnt[i];
}
return ans;
}
}