POJ3070(矩阵快速幂模板)

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstring>
using namespace std;
const int maxn = 3;
const int mod = 10000;
typedef long long LL;
struct node {
    int a[maxn][maxn];
    node() { memset(a, 0, sizeof(a)); }
}ans, si;
LL n;

node multi(node a, node b) {
    node t;
    for(int i = 0; i < 2; ++i)
        for(int j = 0; j < 2; ++j)
            for(int k = 0; k < 2; ++k)
                t.a[i][j] = (t.a[i][j] + a.a[i][k] * b.a[k][j]) % mod;
    return t;
}

int fastpow(LL n) {
    si.a[0][0] = si.a[0][1] = si.a[1][0] = 1;
    si.a[1][1] = 0;
    ans.a[0][0] = ans.a[1][1] = 1;
    ans.a[0][1] = ans.a[1][0] = 0;
    while(n) {
        if(n & 1) ans = multi(ans, si);
        si = multi(si, si);
        n >>= 1;
    }
    return ans.a[0][1];
}

int main() {
    while(scanf("%I64d", &n) != EOF && n != -1) {
        int res = fastpow(n);
        printf("%d\n", res);
    }
    return 0;
}

快速幂运算

int fastpow(int a, int b, int mod) {
    int ans = 1;   /// a 的 b 次方 并取模mod
    a %= mod;
    while(b) {
        if(b & 1) ans = (ans * a) % mod;
        b >>= 1;
        a = (a * a) % mod;
    }
    return ans;
}