1871. Jump Game VII

/**
 * Problem: LeetCode 1871 - Jump Game VII
 * Difficulty: Medium
 * Language: Java
 * Author: CodeByTushu
 */
class Solution {
    public boolean canReach(String s, int minJump, int maxJump) {
        int n = s.length();
        if (s.charAt(n - 1) == '1') {
            return false;
        }

        boolean[] dp = new boolean[n];
        dp[0] = true;
        int reachableInWindow = 0;

        for (int i = 1; i < n; i++) {
            // Add (i - minJump) to sliding window
            if (i >= minJump && dp[i - minJump]) {
                reachableInWindow++;
            }
            // Remove (i - maxJump - 1) from sliding window
            if (i > maxJump && dp[i - maxJump - 1]) {
                reachableInWindow--;
            }

            // Current index is reachable if within valid jump range and character is '0'
            if (s.charAt(i) == '0' && reachableInWindow > 0) {
                dp[i] = true;
            }
        }

        return dp[n - 1];
    }
}

"""
Problem: LeetCode 1871 - Jump Game VII
Difficulty: Medium
Language: Python
Author: CodeByTushu
"""
class Solution:
    def canReach(self, s: str, minJump: int, maxJump: int) -> bool:
        n = len(s)
        if s[n - 1] == '1':
            return False

        dp = [False] * n
        dp[0] = True
        reachable_in_window = 0

        for i in range(1, n):
            # Element entering the sliding window: i - minJump
            if i >= minJump and dp[i - minJump]:
                reachable_in_window += 1
            # Element leaving the sliding window: i - maxJump - 1
            if i > maxJump and dp[i - maxJump - 1]:
                reachable_in_window -= 1

            if s[i] == '0' and reachable_in_window > 0:
                dp[i] = True

        return dp[n - 1]

/**
 * Problem: LeetCode 1871 - Jump Game VII
 * Difficulty: Medium
 * Language: C++
 * Author: CodeByTushu
 */
#include <string>
#include <vector>

using namespace std;

class Solution {
public:
    bool canReach(string s, int minJump, int maxJump) {
        int n = s.length();
        if (s[n - 1] == '1') {
            return false;
        }

        vector<bool> dp(n, false);
        dp[0] = true;
        int reachableInWindow = 0;

        for (int i = 1; i < n; ++i) {
            if (i >= minJump && dp[i - minJump]) {
                reachableInWindow++;
            }
            if (i > maxJump && dp[i - maxJump - 1]) {
                reachableInWindow--;
            }

            if (s[i] == '0' && reachableInWindow > 0) {
                dp[i] = true;
            }
        }

        return dp[n - 1];
    }
};

/**
 * Problem: LeetCode 1871 - Jump Game VII
 * Difficulty: Medium
 * Language: JavaScript
 * Author: CodeByTushu
 */
/**
 * @param {string} s
 * @param {number} minJump
 * @param {number} maxJump
 * @return {boolean}
 */
var canReach = function(s, minJump, maxJump) {
    const n = s.length;
    if (s[n - 1] === '1') {
        return false;
    }

    const dp = new Uint8Array(n);
    dp[0] = 1;
    let reachableInWindow = 0;

    for (let i = 1; i < n; i++) {
        if (i >= minJump && dp[i - minJump]) {
            reachableInWindow++;
        }
        if (i > maxJump && dp[i - maxJump - 1]) {
            reachableInWindow--;
        }

        if (s[i] === '0' && reachableInWindow > 0) {
            dp[i] = 1;
        }
    }

    return dp[n - 1] === 1;
};