【拓扑排序】 HDOJ 1811 Rank of Tetris

来源：互联网发布：淘宝小类目让我发财了编辑：程序博客网时间：2024/05/24 05:21

先用并查集缩点，然后拓扑排序就行了。。。判断信息不完整可以看队列里的元素个数，如果大于1则肯定是信息部完整。。。

#include <iostream>  #include <queue>  #include <stack>  #include <map>  #include <set>  #include <bitset>  #include <cstdio>  #include <algorithm>  #include <cstring>  #include <climits>  #include <cstdlib>#include <cmath>#include <time.h>#define maxn 10005#define maxm 20005#define eps 1e-10#define mod 998244353#define INF 999999999#define lowbit(x) (x&(-x))#define mp mark_pair#define ls o<<1#define rs o<<1 | 1#define lson o<<1, L, mid  #define rson o<<1 | 1, mid+1, R  typedef long long LL;//typedef int LL;using namespace std;LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}void scanf(int &__x){__x=0;char __ch=getchar();while(__ch==' '||__ch=='\n')__ch=getchar();while(__ch>='0'&&__ch<='9')__x=__x*10+__ch-'0',__ch = getchar();}// headint h[maxn], next[maxm], v[maxm];int H[maxn], NEXT[maxm], V[maxm];int f[maxn], in[maxn], id[maxn];char s[100];queue<int> q;int cnt, n, m, CNT;int find(int x){return x == f[x] ? f[x] : f[x] = find(f[x]);}void init(void){cnt = CNT = 0;memset(in, 0, sizeof in);memset(h, -1, sizeof h);memset(H, -1, sizeof H);for(int i = 0; i <= n; i++) f[i] = i;}void addedges(int u, int vv){next[cnt] = h[u], h[u] = cnt, v[cnt] = vv, cnt++;}void Addedges(int u, int vv){NEXT[CNT] = H[u], H[u] = CNT, V[CNT] = vv, CNT++;}void narrow(void){m = 0;for(int i = 0; i < n; i++) if(find(i) == i) id[f[i]] = ++m;for(int i = 0; i < n; i++)for(int e = H[i]; ~e; e = NEXT[e])addedges(id[f[i]], id[f[V[e]]]), in[id[f[V[e]]]]++;}void debug(void){for(int i = 1; i <= m; i++) {printf("%d :: ", i);for(int e = h[i]; ~e; e = next[e])printf("%d ", v[e]);printf("\n");}}void work(void){int ok = 1, a, b, aa, bb, inq, num;while(m--) {scanf("%d%s%d", &a, s, &b);aa = find(a), bb = find(b);if(s[0] == '=') {if(aa > bb) f[aa] = bb;else f[bb] = aa;}if(aa == bb && s[0] != '=') ok = 0;if(s[0] == '>') Addedges(b, a);if(s[0] == '<') Addedges(a, b);}if(!ok) {printf("CONFLICT\n");return;}narrow();inq = num = 0;for(int i = 1; i <= m; i++)if(!in[i]) {q.push(i);inq++, num++;if(inq > 1) ok = 0;}while(!q.empty()) {int u= q.front(); q.pop(), inq--;for(int e = h[u]; ~e; e = next[e]) {in[v[e]]--;if(!in[v[e]]) {q.push(v[e]);inq++, num++;if(inq > 1) ok = 0;}}}if(num < m) printf("CONFLICT\n");else if(!ok) printf("UNCERTAIN\n");else printf("OK\n");}int main(void){while(scanf("%d%d", &n, &m)!=EOF) {init();work();}return 0;}

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