G面经Prepare: Longest All One Substring

give a string, all 1 or 0, we can flip a 0 to 1, find the longest 1 substring after the flipping

 

这是一个简单版本of LC 424 Longest Repeating Character Replacement

又是Window, 又是Two Pointers

Window还是采用每次都try to update left使得window valid, 每次都检查最大window

package GooglePhone;

public class LongestOneSubstr {
    
    public static int find2(String str) {
        if (str==null || str.length()==0) return 0;
        int l = 0, r = 0;
        int maxLen = 0;
        int countZero = 0;
        for (r=0; r<str.length(); r++) {
            if (str.charAt(r) == '0') countZero++;
            while (countZero > 1 && l < str.length()) {
                if (str.charAt(l) == '0') countZero--;
                l++;
            }
            maxLen = Math.max(r-l+1, maxLen);
        }
        return maxLen;
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println(find2("10111000010110111101101010101"));
    }

}