HDU 5399 Too Simple (2015-year School competition 9th game)

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2. Problem-Solving ideas: a discussion of the situation. It was a really easy game, I thought it was (n!) ^ (cnt-1). Ultimate Infinity WA. There are several special cases that require additional judgment. First, if the input, there is a row is not-1 and there are two numbers mapped to the same number, then inevitably no solution, ans=0. Second, if there is no-1, you need to map from the first M function to the 1th function, and check to see if it really becomes a self-mapping at the end. The most likely scenario is that there is at least one-1, so the final answer is (n!) ^ (cnt-1).

3. Code:

#pragma COMMENT (linker, "/stack:1024000000,1024000000") #include <iostream> #include <algorithm># include<cassert> #include <string> #include <sstream> #include <set> #include <bitset># include<vector> #include <stack> #include <map> #include <queue> #include <deque># include<cstdlib> #include <cstdio> #include <cstring> #include <cmath> #include <ctime># Include<cctype> #include <functional>using namespace std; #define ME (s) memset (s,0,sizeof (s)) typedef long Long ll;typedef unsigned int uint;typedef unsigned long long ull;typedef pair <int, int> p;const int N=100+10;const    int mod=1e9+7;ll F[n],a[n][n];int Main () {int n,m;    F[0]=1;    for (int i=1;i<n;i++) f[i]= (f[i-1]*i)%mod;        while (~SCANF ("%d%d", &n,&m)) {ll ans=1,tot=0;            for (int i=0;i<m;i++) {scanf ("%i64d", &a[i][1]);            if (a[i][1]==-1) tot++; else for (int j=2;j< =n;j++) {scanf ("%i64d", &a[i][j]);  for (int k=j-1;k>=1;k--) if (a[i][k]==a[i][j]) ans=0;        If a row exists with two numbers mapped to the same number, no solution}} for (int i=1;i<tot;i++) ans= (ans*f[n])%mod;            if (!tot) {ll x[n];            for (int i=1;i<=n;i++) x[i]=i;            for (int. i=m-1;i>=0;i--) for (int j=1;j<=n;j++) {x[j]=a[i][x[j]];  } for (int i=1;i<=n;i++) if (x[i]!=i) ans=0;    Not self-mapping, no Solution} printf ("%i64d\n", ans); }}

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HDU 5399 Too Simple (2015-year School competition 9th game)