中国余数定理

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--> 1 void extended_gcd(int a,int b,int *x,int *y)
 2 {
 3     int t;
 4     if(b==0)
 5     {
 6         *x = 1;
 7         *y = 0;
 8         return ;
 9     }
10     extended_gcd(b,a%b,x,y);
11     t = *x;
12     *x = *y;
13     *y = t - a/b*(*x);
14 }
15 
16 int crt(int a[],int m[], int n)
17 {
18     int lcm,i,ans,Mi,x,y;
19     lcm = 1;
20     for(i=0;i<n;i++)
21         lcm *= m[i];
22     ans = 0;
23     for(i=0;i<n;i++)
24     {
25         Mi = lcm/m[i];
26         extended_gcd(Mi,m[i],&x,&y);
27         ans += Mi*x*a[i];
28     }
29     ans %= lcm;
30     while(ans<0)
31         ans += lcm;
32     return ans;
33 }

 

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-->#include <stdio.h>
#include <stdlib.h>

void extended_gcd(int a,int b,int *x,int *y)
{
    int t;
    if(b==0)
    {
        *x = 1;
        *y = 0;
        return ;
    }
    extended_gcd(b,a%b,x,y);
    t = *x;
    *x = *y;
    *y = t - a/b*(*x);
}

int crt(int a[],int m[], int n)
{
    int lcm,i,ans,Mi,x,y;
    lcm = 1;
    for(i=0;i<n;i++)
        lcm *= m[i];
    ans = 0;
    for(i=0;i<n;i++)
    {
        Mi = lcm/m[i];
        extended_gcd(Mi,m[i],&x,&y);
        ans += Mi*x*a[i];
    }
    ans %= lcm;
    while(ans<0)
        ans += lcm;
    return ans;
}

int main()
{
    int i, k;
    int *b, *m;
    while(1)
    {
        scanf("%d", &k);
        b = (int*)malloc(sizeof(int) * k);
        m = (int*)malloc(sizeof(int) * k);
        if(!k)
            break;
        for(i = 0; i < k; i ++)
            scanf("%d", &b[i]);
        for(i = 0; i < k; i ++)
            scanf("%d", &m[i]);
        printf("%d
", crt(b, m, k));
        free(b);
        free(m);
    }
    return 0;
}