ACM-STL-vecto內存釋放：計蒜客：堆積木

題目鏈接：https://www.jisuanke.com/course/1451/83475
原來vector的clear函數並不釋放內存…

vector<int>k;
k.swap(amap[b]);

swap括號內的是要釋放的vector地址，爆內存wa掉兩次，以下是ac代碼

#include<bits/stdc++.h>
using namespace std;
int main()
{

    int n, m, a, b;
    scanf("%d%d",&n,&m);
    vector<int> amap[n+5];
    for(int i = 0; i < n; i++)
        amap[i].push_back(i + 1);
    while(m--)
    {
        scanf("%d%d",&a,&b);
        if(a != b)
        {
            a--;
            b--;
            for(int i = 0; i < amap[b].size(); i++)
                amap[a].push_back(amap[b][i]);
            vector<int>k;
            k.swap(amap[b]);
        }
        else
            ;
    }
    for(int i = 0; i < n; i++)
    {
        if(amap[i].empty())
            ;
        else
        {
            int j;
            for(j = 0; j < amap[i].size(); j++)
            {
                printf("%d",amap[i][j]);
                if( j != amap[i].size() - 1)
                    printf(" ");
            }
        }
        printf("\n");
    }
    return 0;
}