hdu X问题 (中国剩余定理不互质)

http://acm.hdu.edu.cn/showproblem.php?pid=1573

X问题

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 4439    Accepted Submission(s): 1435


Problem Description
求在小于等于N的正整数中有多少个X满足:X mod a[0] = b[0], X mod a[1] = b[1], X mod a[2] = b[2], …, X mod a[i] = b[i], … (0 < a[i] <= 10)。
 
Input
输入数据的第一行为一个正整数T,表示有T组测试数据。每组测试数据的第一行为两个正整数N,M (0 < N <= 1000,000,000 , 0 < M <= 10),表示X小于等于N,数组a和b中各有M个元素。接下来两行,每行各有M个正整数,分别为a和b中的元素。
 
Output
对应每一组输入,在独立一行中输出一个正整数,表示满足条件的X的个数。
 
Sample Input
3
10 3
1 2 3
0 1 2
100 7
3 4 5 6 7 8 9
1 2 3 4 5 6 7
10000 10
1 2 3 4 5 6 7 8 9 10
0 1 2 3 4 5 6 7 8 9
 
Sample Output
1
0
3
 
这道题除数不是两两互质的,也就不能直接套用中国剩余定理模板,既然不能直接套用就两两合成
 
#include<stdio.h>
#include<algorithm>
#include<string.h>
#include<stdlib.h>

using namespace std;

const int M = 20;
typedef long long ll;
int r;
ll n[M], b[M], N;

void gcd(ll a, ll b, ll &x, ll &y)
{
    if(b == 0)
    {
        x = 1;
        y = 0;
        r = a;
        return ;
    }
    gcd(b, a % b, x, y);
    ll t = x;
    x = y;
    y = t - a / b * y;
}
ll CRT2(ll b[], ll n[], int m)
{
    int f = 0;
    ll n1 = n[0], n2, b1 = b[0], b2, c, t, k, x, y;
    for(int i = 1 ; i < m ; i++)
    {
        n2 = n[i];
        b2 = b[i];
        c = b2 - b1;
        gcd(n1, n2, x, y);
        if(c % r != 0)
        {
            f = 1;
            break;
        }
        k = c / r * x;
        t = n2 / r;
        k = (k % t + t) % t;
        b1 = b1 + n1 * k;
        n1 = n1 * t;
    }
    if(f)//无解
        return 0;
    if(b1 == 0)
        b1 = n1;
    if(b1 > N)
        return 0;
    return (N - b1) / n1 + 1;
}

int main()
{
    int t, m;
    scanf("%d", &t);
    while(t--)
    {
        scanf("%lld%d", &N, &m);
        for(int i = 0 ; i < m ; i++)
            scanf("%lld", &n[i]);
        for(int i = 0 ; i < m ; i++)
            scanf("%lld", &b[i]);
        printf("%lld
", CRT2(b, n, m));
    }
    return 0;
}
 
原文地址:https://www.cnblogs.com/qq2424260747/p/4962598.html