在线等，Java 小白诚求编写一道很简单的算法题，立即给分

    public int solution(String input) {
        if (input == null || input.length() == 0) {
            return -1; // Input Error
        }

        // Step1: 统计开闭括号个数
        int leftTotal = 0; // 开括号个数
        for (int i = 0; i < input.length(); i++) {
            char ch = input.charAt(i);
            if (ch == '(') {
                leftTotal++;
            } else if (ch == ')') {
                // Do nothing
            } else {
                return -1; // Input Error
            }
        }
        int rightTotal = input.length() - leftTotal; // 闭括号个数

        // Step2: 遍历计算
        int leftCount = 0;
        for (int i = 1; i <= input.length(); i++) {
            char ch = input.charAt(i - 1);
            if (ch == '(') {
                leftCount++;
            }
            int rightCount = rightTotal - (i - leftCount); // 关键
            if (rightCount == leftCount) { // Success
                return i;
            }
        }

        return 0; // Not Found
    }

NOTE：输入里不要出现空格

public class Solution {
public int solution(String s) {
char c1 = '(';
char c2 = ')';
int in = s.length();
int i = in%2==0?in/2:in/2+1;
int k1 = 0;
int k2 = 0;
int j = 0;
char[] cs = s.toCharArray();
for (int j1 = 0; j1 < i; j1++) {
if(c1==cs[j1]){
++k1;
}
}
for (int j2 = in-1; j2 > i; j2--) {
if(c2==cs[j2]){
++k2;
}
}
if(k1==k2){
return k1;
}else if(k1<k2){
for (int k = 0; k < in-i; k++) {
if(c1==cs[k+i]){
++k1;
}else{
--k2;
}

            if(k1==k2){
                j = k1;
                break;
            }
        }
    }else{
        for (int k = in-1; k < i; k--) {
            if(c2==cs[k]){
                --k1;
            }else{
                ++k2;
            }

            if(k1==k2){
                j = k2;
                break;
            }
        }
    }
    return j;
}

}

public class Solution {

public int solution(String s) {
    char c1 = '(';
    char c2 = ')';
    int in = s.length();
    int i = in%2==0?in/2:in/2+1;
    int k1 = 0;
    int k2 = 0;
    int j = 0;
    char[] cs = s.toCharArray();
    for (int j1 = 0; j1 < i; j1++) {
        if(c1==cs[j1]){
            ++k1;
        }
    }
    for (int j2 = in-1; j2 > i; j2--) {
        if(c2==cs[j2]){
            ++k2;
        }
    }
    if(k1==k2){
        j = k1;
    }else if(k1<k2){
        for (int k = 0; k < in-i; k++) {
            if(c1==cs[k+i]){
                ++k1;
            }else{
                --k2;
            }

            if(k1==k2){
                j = k1;
                break;
            }
        }
    }else{
        for (int k = in-1; k > i; k--) {
            if(c2==cs[k]){
                --k1;
            }else{
                ++k2;
            }

            if(k1==k2){
                j = k2;
                break;
            }
        }
    }
    int q = in-1;
    int ini = 0;
    while(ini<j){
        if(cs[q--]==c2){
            ini++;
        }
    }
    return q;
}

}