求大数高次幂的模
2019-04-13 22:05发布
生成海报
题目:
/*
球大数高次幂的模
X^Y mod Z
思路:
x^y mod z = (x % z)*(x % z)*、、、*(x % z)
*/
#include
bool Getmi(int X, int Y, int Z, int &res)
{
int numl(1);
int numy(Y);
int multi(X);
int tmp(0);
int tres(1);
multi = multi % Z;
if(multi > 1) //当余数等于0、1时直接可求得结果
while(numy > 0)
{
if(multi == 1)break;//当余数等于1时结束循环
numl = 1;
int tt = numy;
X = multi;
while(X < Z && tt > 0 )
{
X *= multi;
tt--;
numl++;
}
tmp = numy % numl;
while(tmp)
{
if(multi == 1)break;
tres *= multi;
tmp--;
}
multi = X % Z;
numy = numy / numl;
tres %= Z;
}
res = (multi * tres) % Z;
return true;
}
int main()
{
int x, y, z;
int res(0);
while(1)
{
res = 0;
printf("请输入x, y, z:");
scanf("%d %d %d", &x, &y, &z);
if(Getmi(x, y, z, res))
{
printf("result = %d
", res);
}
else
{
printf("Wrong!!!
");
}
}
}
测试结果:
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