poj2947 Widget Factory

模意义下整数高斯消元

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
int n, m, k, uu, a[305][305];
char ss[15];
int getDay(){
	if(ss[0]=='M')	return 1;
	if(ss[0]=='T' && ss[1]=='U')	return 2;
	if(ss[0]=='W')	return 3;
	if(ss[0]=='T' && ss[1]=='H')	return 4;
	if(ss[0]=='F')	return 5;
	if(ss[0]=='S' && ss[1]=='A')	return 6;
	if(ss[0]=='S' && ss[1]=='U')	return 7;
}
int gauss(){
	int hmn=1;
	for(int i=1; i<=n; i++){
		int maxi=0;
		for(int j=hmn; j<=m; j++)
			if(a[j][i]){
				maxi = j;
				break;
			}
		if(maxi){
			swap(a[maxi], a[hmn]);
			for(int j=hmn+1; j<=m; j++)
				if(a[j][i]){
					int bei1=a[hmn][i];
					int bei2=a[j][i];
					for(int l=i; l<=n+1; l++)
						a[j][l] = ((a[j][l] * bei1 - a[hmn][l] * bei2) % 7 + 7) % 7;
				}
				hmn++;
		}
	}
	for(int i=hmn; i<=m; i++)
		if(a[i][n+1])
			return -1;
	if(hmn<=n)	return 1;
	for(int i=n; i>=1; i--){
		for(int j=i+1; j<=n; j++){
			a[i][n+1] = ((a[i][n+1] - a[j][n+1] * a[i][j])%7 + 7) % 7;
			a[i][j] = 0;
		}
		while(a[i][n+1]%a[i][i])	a[i][n+1] += 7;
		a[i][n+1] /= a[i][i];
		a[i][i] = 1;
		if(a[i][n+1]<=2)	a[i][n+1] += 7;
	}
	return 0;
}
int main(){
	while(scanf("%d %d", &n, &m)!=EOF){
		if(!n && !m)	break;
		memset(a, 0, sizeof(a));
		for(int i=1; i<=m; i++){
			scanf("%d %s", &k, ss);
			int tmp1=getDay();
			scanf("%s", ss);
			a[i][n+1] = (getDay()-tmp1+1+7) % 7;
			while(k--){
				scanf("%d", &uu); 
				a[i][uu] = (a[i][uu] + 1) % 7;
			}
		}
		int re=gauss();
		if(re==-1)	printf("Inconsistent data.\n");
		else if(re==1)	printf("Multiple solutions.\n");
		else{
			for(int i=1; i<n; i++)
				printf("%d ", a[i][n+1]);
			printf("%d\n", a[n][n+1]);
		}
	}
	return 0;
}