题解 | 数组分组

#include<iostream>
#include<algorithm>
#include<vector>
#include<math.h>
using namespace std;

bool judge(int i, vector<int>& arr, int sum1, int sum2){ //剩余的数组中组合出等于3和5和之差的
    if(i == arr.size())
        return abs(sum1) == sum2;
    else //加放一边，减放另一边
        return judge(i + 1, arr, sum1 + arr[i], sum2) || judge(i + 1, arr, sum1 - arr[i], sum2);
}

int main(){
    int n;
    while(cin >> n){
        vector<int> arr;
        int sum3 = 0;
        int sum5 = 0;
        int rest = 0;
        for(int i = 0; i < n; i++){ 
            int x;
            cin >> x;
            if(x % 5 == 0) //先求一个组的和
                sum5 += x;
            else if(x % 3 == 0) //再求另一个组的和
                sum3 += x;
            else{
                arr.push_back(x); //剩余的加入数组并求和
            }
        }
        if(judge(0, arr, 0, abs(sum5 - sum3)))
            cout << "true" << endl;
        else
            cout << "false" << endl;
    }
    return 0;
}