403-frog-jump.js

/**
 * @param {number[]} stones
 * @return {boolean}
 */
var canCross = function (stones) {
  const n = stones.length;
  const dp = new Array(n).fill(0).map(() => new Array(n).fill(false));
  dp[0][0] = true;
  for (let i = 1; i < n; i++) {
    for (let j = i - 1; j >= 0; j--) {
      const diff = stones[i] - stones[j];
      if (diff > j + 1) {
        break;
      }
      dp[i][diff] = dp[j][diff - 1] || dp[j][diff] || dp[j][diff + 1];
      if (i === n - 1 && dp[i][diff]) {
        return true;
      }
    }
  }
  return false;
};