https://leetcode.com/problems/frog-jump/

frogJump.js

/**
 * @param {number[]} stones
 * @return {boolean}
 */
var canCross = function(stones) {
    
    if(stones[1] !== 1) return false;
    
    const map = new Map();
    stones.forEach((distance, index) => {
        map.set(distance, index);
    });
    
    const memo = new Array(stones.length).fill(0).map(() => new Array(stones.length).fill(null));
    
    const r = (i, prev) => {
        
        if(i === stones.length-1) return true;
        
        if(memo[i][prev] !== null) return memo[i][prev];
        
        const lastJumpDistance = stones[i] - stones[prev];
        
        const jumpMore = stones[i] + lastJumpDistance + 1;
        if(map.has(jumpMore) && r(map.get(jumpMore), i)) return memo[i][prev] = true;
        
        const jumpSame = stones[i] + lastJumpDistance;
        if(map.has(jumpSame) && r(map.get(jumpSame), i)) return memo[i][prev] = true;
        
        if(lastJumpDistance <= 1) return memo[i][prev] = false;

        const jumpLess = stones[i] + lastJumpDistance - 1;
        if(map.has(jumpLess) && r(map.get(jumpLess), i)) return memo[i][prev] = true;
        return memo[i][prev] = false;
    };
    
    return r(1, 0);
};