42 lines
879 B
C++
42 lines
879 B
C++
#include<iostream>
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#include<string.h>
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#include<cstdio>
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using namespace std;
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#define M 1000
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int num[M],a[M],b[M];
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int c1[M],c2[M];
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#define mod 100
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#define LL long long
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int main()
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{
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int n,m;
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while(scanf("%d %d",&n,&m)!=EOF)
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{
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for(int i=0;i<n;i++)
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cin>>a[i]>>b[i];
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memset(c1,0,sizeof(c1));
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memset(c2,0,sizeof(c2));
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for(int i=a[0];i<=b[0];i++)
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{
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c1[i]=1;
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}
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for(int i=1;i<n;i++)
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{
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for(int j=0;j<=m;j++)
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{
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for(int k=a[i];k+j<=m&&k<=b[i];k++)
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{
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c2[j+k]+=c1[j];
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}
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}
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for(int j=0;j<=m;j++)
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{
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c1[j]=c2[j];
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c2[j]=0;
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}
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}
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cout<<c1[m]<<endl;
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}
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return 0;
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}
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