1010. Radix (25)

#include "stdafx.h"
#include <iostream>
#include <string.h>using namespace std;long long getnumbychar(char c)
{long long num;if(c >= '0' && c <= '9'){num = c - '0';}else {num = c - 'a' + 10;}return num;
}long long getradix(char s[])
{int len = strlen(s), i;long long cur, radix = -1;for(i = 0; i < len; i++){cur = getnumbychar(s[i]);if(cur > radix){radix = cur;}}radix++;if(radix < 2){radix = 2;}return radix;
}long long getnum(char s[], long long radix)
{int len = strlen(s), i;long long num = 0, cur;for(i = 0; i < len; i++){cur = getnumbychar(s[i]);num = num * radix + cur;}return num;
}long long getres(char s[], long long low, long long high, long long goal)
{long long mid, cur;while(low < high){mid = (low + high) / 2;cur = getnum(s, mid);if(cur < 0 || cur >= goal){high = mid;}else{low = mid + 1;}}return high;
}int main()
{char n1[20], n2[20];int tag;long long radix;scanf("%s%s%d%lld", n1, n2, &tag, &radix);char temp[20];if(tag == 2){strcpy(temp, n1);strcpy(n1, n2);strcpy(n2, temp);}long long low = getradix(n2), goal = getnum(n1, radix), high = goal + 1;long long res = getres(n2, low, high, goal);if(getnum(n2, res) == goal){printf("%lld\n", res);}else{printf("Impossible\n");}system("pause");return 0;
}