贪心算法处理分配问题

881. Boats to Save People

Medium

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The ​​i​​​-th person has weight ​​people[i]​​​, and each boat can carry a maximum weight of ​​limit​​.

Each boat carries at most 2 people at the same time, provided the sum of the weight of those people is at most ​​limit​​.

Return the minimum number of boats to carry every given person.  (It is guaranteed each person can be carried by a boat.)

 

Example 1:

Input: people = [1,2], limit = 3 Output: 1 Explanation: 1 boat (1, 2)

Example 2:

Input: people = [3,2,2,1], limit = 3 Output: 3 Explanation: 3 boats (1, 2), (2) and (3)

Example 3:

Input: people = [3,5,3,4], limit = 5 Output: 4 Explanation: 4 boats (3), (3), (4), (5)

class Solution {
public:
    int numRescueBoats(vector<int>& people, int limit) {
        sort(people.begin(),people.end());
        int Result = 0;int LeftIndex = 0;
        int RightIndex = people.size() - 1;
        while(LeftIndex < RightIndex){
            while(LeftIndex < RightIndex && people[LeftIndex] + people[RightIndex] > limit){
                RightIndex--;
                Result++;
            }
            LeftIndex++;
            RightIndex--;
            Result++;
        }
        if(LeftIndex == RightIndex){
            Result++;
        }
        return Result;
    }
};