C# 数学 代码
public class Solution {
public int PivotInteger(int n) {
int x = (int)Math.Sqrt(n * (n + 1) / 2);
return x * x == n * (n + 1) / 2 ? x : -1;
}
}
C# 暴力枚举 代码
public class Solution {
public int PivotInteger(int n) {
for (int i = 1; i <= n; i++){
if ((1 + i) * i == (i + n) * (n - i + 1)) return i;
}
return -1;
}
}