Leetcode 1552. Magnetic force between two balls

topic

Leetcode 1552. Magnetic force between two balls

Code (9.17 first brush to see the analysis)

Didi 9.15 written test questions

class Solution {
    
    
public:
    bool check(int x, vector<int>& position, int m) {
    
    
        int pre = position[0], cnt = 1;
        for(int i = 1; i < position.size(); ++i) {
    
    
            if(position[i] - pre >= x) {
    
        // 累计可以放下球的个数
                pre = position[i];
                cnt += 1;
            }
        }
        return cnt >= m;
    }
    int maxDistance(vector<int>& position, int m) {
    
    
        sort(position.begin(), position.end());
        int left = 1, right = position.back()-position[0], ans = -1;
        while(left <= right) {
    
    
            int mid = (left+right)/2;
            if(check(mid, position, m)) {
    
       // 若放得下m个球，增大球间距
                ans = mid;
                left = mid+1;
            } else {
    
        // 若放不下则减少球间距
                right = mid -1;
            }
        }
        return ans;
    }
};