1871. Jump Game VII

class Solution {
    public boolean canReach(String s, int minJump, int maxJump) {
        int n = s.length();
        boolean[] dp = new boolean[n];
        char[] ch = s.toCharArray();
        
        dp[0] = ch[0]=='0';
        
        int reachable = 0;
        
        for(int i = 1;i<n;i++){
            
            if(i>=minJump){
                reachable += dp[i-minJump]? 1 : 0;
            }
            
            if(i>maxJump){
                reachable -= dp[i-maxJump-1]? 1 : 0;
            }
            
            dp[i] = reachable>0 && ch[i] == '0';
        }
        
        return dp[n-1];
    }
}