32 lines
656 B
C++
32 lines
656 B
C++
//http://contest-hunter.org:83/contest/0x3B%E3%80%8C%E6%95%B0%E5%AD%A6%E7%9F%A5%E8%AF%86%E3%80%8D%E7%BB%83%E4%B9%A0/3B04%20Xiao%209*%E5%A4%A7%E6%88%98%E6%9C%B1%E6%9C%80%E5%AD%A6
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#include<cstdio>
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#include<cassert>
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typedef long long LL;
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LL exgcd(LL a,LL b,LL &x,LL &y)
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{
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if(b==0) { x=1; y=0; return a; }
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LL d=exgcd(b,a%b,y,x);
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y-=x*(a/b);
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return d;
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}
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int n;
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LL x,L,t,r,a,m,d;
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int main()
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{
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#ifdef local
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freopen("pro.in","r",stdin);
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#endif
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scanf("%d",&n);
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scanf("%lld%lld",&m,&a); x=a; L=m;
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for(int i=2;i<=n;i++)
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{
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scanf("%lld%lld",&m,&a);
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d=exgcd(L,m,t,r);
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x+=((a-x)%m+m)%m/d*t*L;
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L=L/d*m;
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x=(x%L+L)%L;
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}
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printf("%lld\n",x);
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return 0;
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}
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