Luogu3090 [USACO13NOV]空荡荡的摊位Empty Stalls (动态规划)

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#define R(a,b,c) for(register int  a = (b); a <= (c); ++ a)
#define nR(a,b,c) for(register int  a = (b); a >= (c); -- a)
#define Max(a,b) ((a) > (b) ? (a) : (b))
#define Min(a,b) ((a) < (b) ? (a) : (b))
#define Fill(a,b) memset(a, b, sizeof(a))
#define Swap(a,b) a^=b^=a^=b
#define ll long long
#define ON_DEBUG

#ifdef ON_DEBUG

#define D_e_Line printf("\n\n----------\n\n")
#define D_e(x)  cout << #x << " = " << x << endl
#define Pause() system("pause")

#else

#define D_e_Line ;

#endif

struct ios{
    template<typename ATP>ios& operator >> (ATP &x){
        x = 0; int f = 1; char c;
        for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-')  f = -1;
        while(c >= '0' && c <= '9') x = x * 10 + (c ^ '0'), c = getchar();
        x*= f;
        return *this;
    }
}io;
using namespace std;

int f[3000007];

int main(){
	int n, m;
	io >> n >> m;
	R(i,1,m){
		int x, y, a, b;
		io >> x >> y >> a >> b;
		R(j,1,y)
			f[1ll * (1ll * a * j + b) % n] += x;
	}

	int flag = false;
	while(!flag || f[0] > 1){
		R(i,0,n - 1){
			if(f[i] > 1){
				f[(i + 1) % n] += f[i] - 1;
				f[i] = 1;
			}
		}
		flag = true;
	}

	R(i,0,n){
		if(f[i] == 0){
			printf("%d", i);
			return 0;
		}
	}

	return 0;
}