uva 12356 Army Buddies

简单的并查集应用。

#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
using namespace std;
const int maxn = 100000 + 10;
int ll[maxn], rr[maxn];
int f1(int x)
{
    if (x != ll[x]) ll[x] = f1(ll[x]);
    return ll[x];
}
int f2(int x)
{
    if (x != rr[x]) rr[x] = f2(rr[x]);
    return rr[x];
}
int main()
{
    int n, m, i, a, b, j;
    while (~scanf("%d%d", &n, &m))
    {
        if (n == 0 && m == 0) break;
        for (i = 0; i <= n; i++) ll[i] = i, rr[i] = i;
        for (i = 0; i < m; i++)
        {
            scanf("%d%d", &a, &b);
　　　　　　　for (j = a; j <= b; j++) ll[j] = a;
            ll[a] = a - 1;
            for (j = a; j <= b; j++) rr[j] = b;
            rr[b] = b + 1;
            int zuo = f1(a);
            int you = f2(b);
            if (zuo == 0 || zuo == n + 1) printf("* ");
            else printf("%d ", zuo);
            if (you == n + 1 || you == 0) printf("*
");
            else printf("%d
", you);
        }
        printf("-
");
    }
    return 0;
}