​​题目​​

typedef long long int _int;
class Solution {
public:
    _int ugly[2000];
    _int num[2000];
    int nthUglyNumber(int n) {
       
        ugly[0]=1;
        int x=0,y=0,z=0;
        int pos=1;
        while(pos<n)
        {
            int a = min(2*ugly[x],min(3*ugly[y],5*ugly[z]));
            
            if(a==2*ugly[x])
                x++;
            if(a==3*ugly[y])
                y++;
            if(a==5*ugly[z])
                z++;
            
            ugly[pos++]=a;
        }
        
        return ugly[n-1];
        
    }
};