29 lines
518 B
C++
29 lines
518 B
C++
#include <iostream>
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using namespace std;
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typedef long long LL;
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const int mod = 1e9 + 7;
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/*
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测试用例:
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10000000 10000000
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答案：
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999300007
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*/
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//快速乘，计算a*b%mod
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LL ksc(LL a, LL b) {
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LL ans = 0;
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a %= mod;
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while (b) {
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if (b & 1) ans = (ans + a) % mod;
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b >>= 1; //位运算，右移1位，相当于除以2
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a = (a + a) % mod;
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}
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return ans;
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}
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int main() {
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LL a, b;
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cin >> a >> b;
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printf("%lld\n", ksc(a, b));
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return 0;
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}
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