PAT 1048. Find Coins

two sum题目，算是贪婪吧

#include <cstdio>

#include <cstdlib>

#include <vector>

#include <algorithm>



using namespace std;



int main() {

    int N, M;

    scanf("%d%d", &N, &M);

    

    vector<int> coins(N);

    for (int i=0; i<N; i++) {

        scanf("%d", &coins[i]);

    }

    

    sort(coins.begin(), coins.end());

    

    int p = 0, q = N - 1;

    while (p<q) {

        int sum = coins[p] + coins[q];

        if (sum > M) {

            // bigger, so decrease it, move q to the smaller coins

            q--;

        } else if (sum < M) {

            // smaller, so increase it, move p to the bigger coins

            p++;

        } else {

            // we found the coins

            printf("%d %d\n", coins[p], coins[q]);

            break;

        }

    }

    if (p >= q) {

        printf("No Solution\n");

    }

    return 0;

}