Leetcode——171. Excel Sheet Column Number

题目

解答

class Solution {
public:
int titleToNumber(string s) {
int res=0;
for(int i=0;i<s.length();i++)
{
res=res*26+(s[i]-'A'+1);
}
return res;
}
};

class Solution {
public:
string convertToTitle(int n) {
string res="";
while(n>0)
{
if(n%26==0)
{
res="Z"+res;
n=n/26-1;
}
else
{
res= (char)(n%26+'A'-1)+res;
n=n/26;
}

}
return res;
}
};

string convertToTitle(int n) {
string ans;
while (n) {
ans = char ((n - 1) % 26 + 'A') + ans;
n = (n - 1) / 26;
}
return ans;
}