LeetCode 881. 救生艇

public:
    int numRescueBoats(vector<int>& people, int limit) {
        sort(people.begin(), people.end());
        int res = 0, left = 0, right = people.size() - 1;
        while(left <= right) {
            if(people[left] + people[right] <= limit){
                res ++;
                left++;
                right --;
            }
            else {
                res ++;
                right --;
            }
        }
        return res;
    }
};