Submission #1675657

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Source Code Expand

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
typedef long long ll ;
#define rep(i, a, b) for (int i = a; i <= b; ++ i) 
const int N = 510, mo = 1000000007 ;
using namespace std ;

int n, m, col, e, ter[N], nxt[N], lnk[N], id[N], cnt, top, ans, d[N] ;
bool vis[N], ins[N], h[N] ;
int dfn[N], low[N], st[N] ;
struct edge {
	int x, y ; 
} E[N] ;

int gcd(int x, int y) {
	return (y ? gcd(y, x % y) : x) ;
}

void add(int x, int y, int z) {
	ter[++ e] = y, nxt[e] = lnk[x], lnk[x] = e, id[e] = z ;
}

inline int INP(int x) {
	if (!h[x]) {
		h[x] = true ;
		d[++ d[0]] = x ;
		return 1 ;
	}
	return 0 ;
}

inline void OUP() {
	rep(i, 1, d[0]) {
		h[d[i]] = false ;
	}
}

inline int mul(int a, int b) {
	int ans = 1, w = a % mo ;
	for ( ; b; b /= 2) {
		if (b & 1) ans = (ll) ans * w % mo ;
		w = (ll) w * w % mo ;
	}
	return ans ;
} 

inline int calc_cir(int x) {
	int res = 0 ; 
	rep(i, 0, x - 1) {
		res = (res + mul(col, gcd(i, x))) % mo ;
	}
	res = (ll) res * mul(x, mo - 2) % mo ;
	return res ;
}

inline int C(int x, int y) {
	int res = 1 ;
	rep(i, 2, x) res = (ll) res * i % mo ;
	rep(i, 2, y) res = (ll) res * mul(i, mo - 2) % mo ;
	rep(i, 2, x - y) res = (ll) res * mul(i, mo - 2) % mo ;
	return res ;
}

inline int calc_u(int x) {
	return C(col + x - 1, col - 1) ;
}

void dfs(int p, int las) {
	//printf("----- V : %d\n", p) ;
	dfn[p] = low[p] = ++ cnt ;
	for (int i = lnk[p]; i; i = nxt[i]) {
		if (!dfn[ter[i]]) {
			st[++ top] = id[i], ins[id[i]] = true, vis[id[i]] = false ;
			dfs(ter[i], p) ;
			low[p] = min(low[p], low[ter[i]]) ;
			if (low[ter[i]] >= dfn[p]) {
				int poi = 0, ed = 0 ;
				d[0] = 0 ;
				for ( ; ; ) {
					poi += INP(E[st[top]].x) ;
					poi += INP(E[st[top]].y) ;
					++ ed ;
					ins[st[top]] = false ;
					-- top ;
					if (st[top + 1] == id[i]) break ;
				}
				OUP() ;
				if (poi == ed) ans = (ll) ans * calc_cir(ed) % mo /*, printf("Find ---- poi = %d ; ed = %d ; ans *= %d\n", poi, ed, calc_cir(ed)) */;
					else ans = (ll) ans * calc_u(ed) % mo /*, printf("Find ---- poi = %d ; ed = %d ; ans *= %d\n", poi, ed, calc_u(ed))*/ ;
			}
		} else {
			if (vis[id[i]]) {
				vis[id[i]] = false ;
				st[++ top] = id[i] ;
				ins[id[i]] = true ;
			}
			if (ins[id[i]]) low[p] = min(low[p], dfn[ter[i]]) ;
		}
	}
}

int main() {
	scanf("%d%d%d", &n, &m, &col) ;
	int x, y ;
	rep(i, 1, m) {
		scanf("%d%d", &x, &y) ;
		add(x, y, i), add(y, x, i) ;
		E[i].x = x, E[i].y = y ;
	}
	memset(vis, true, sizeof(vis)) ;
	memset(ins, false, sizeof(ins)) ;
	ans = 1 ;
	cnt = top = 0 ;
	rep(i, 1, n) if (!dfn[i]) {
		dfs(i, 0) ;
	}
	printf("%d\n", (ans + mo) % mo) ;
	return 0 ; 
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:106:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d", &n, &m, &col) ;
                                ^
./Main.cpp:109:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &x, &y) ;
                         ^

Judge Result