Submission #2241478

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Source Code Expand

#include<bits/stdc++.h>
#define rep(i,x,y) for (int i=(x); i<=(y); i++)
#define ll long long
#define N 405
#define mod 1000000007
using namespace std;
int n,c,a[N],b[N],sum[N][N],f[2][N];
void upd(int &x,int y){ x+=y; if (x>=mod) x-=mod; }
void pre(){
	rep (i,1,N-1){//sum[i][j]=1^j+2^j+3^j+...+i^j;
		sum[i][0]=1;
		rep (j,1,N-1) sum[i][j]=(ll)sum[i][j-1]*i%mod;//i^j
		rep (j,0,N-1) upd(sum[i][j],sum[i-1][j]);
	}
}
int main(){
	scanf("%d%d",&n,&c);
	pre();
	rep (i,1,n) scanf("%d",&a[i]);
	rep (i,1,n) scanf("%d",&b[i]);
	int nk=0,k=1;
	f[0][0]=1;//f[i][j]表示前i个小朋友分了j颗糖
	rep (i,0,n-1){
		k^=1; nk^=1; memset(f[nk],0,sizeof(f[nk]));
		rep (j,0,c) for (int t=0; t+j<=c; t++)//这一轮分了t颗糖
			upd(f[nk][t+j],(ll)f[k][j]*(sum[b[i+1]][t]+mod-sum[a[i+1]-1][t])%mod);
	}
	printf("%d\n",f[nk][c]);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:17:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&c);
                     ^
./Main.cpp:19:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  rep (i,1,n) scanf("%d",&a[i]);
                               ^
./Main.cpp:20:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  rep (i,1,n) scanf("%d",&b[i]);
                               ^

Judge Result