题解 | #最长山脉#

/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 *
 * @param nums int整型一维数组
 * @return int整型
 */
function longestmountain(nums) {
    // write code here
    let dp = new Array(nums.length);
    dp[0] = 1;
    let direction = "top";
    for (let i = 1; i < nums.length; i++) {
        if (direction === "top") {
            if (nums[i - 1] < nums[i]) {
                dp[i] = dp[i - 1] + 1;
            } else if (nums[i - 1] > nums[i]) {
                direction = "bottom";
                dp[i] = dp[i - 1] + 1;
            } else {
                dp[i] = 1;
            }
        } else {
            if (nums[i - 1] > nums[i]) {
                dp[i] = dp[i - 1] + 1;
            } else if (nums[i - 1] < nums[i]) {
                direction = "top";
                 dp[i] = 2;
            } else {
                direction = "top";
                dp[i] = 1;
            }
        }
    }
    const length = Math.max(...dp);
    return length >= 3 ? length : 0;
}
module.exports = {
    longestmountain: longestmountain,
};