LeetCode-in-Java
335. Self Crossing
Hard
You are given an array of integers distance.
You start at point (0,0) on an X-Y plane and you move distance[0] meters to the north, then distance[1] meters to the west, distance[2] meters to the south, distance[3] meters to the east, and so on. In other words, after each move, your direction changes counter-clockwise.
Return true if your path crosses itself, and false if it does not.
Example 1:
Input: distance = [2,1,1,2]
Output: true
Example 2:
Input: distance = [1,2,3,4]
Output: false
Example 3:
Input: distance = [1,1,1,1]
Output: true
Constraints:
1 <= distance.length <= 1051 <= distance[i] <= 105
Solution
public class Solution {
public boolean isSelfCrossing(int[] x) {
if (x.length < 4) {
return false;
}
for (int i = 3; i < x.length; i++) {
if (x[i - 1] <= x[i - 3] && x[i] >= x[i - 2]) {
return true;
}
if (i > 4
&& x[i] >= x[i - 2] - x[i - 4]
&& x[i - 1] >= x[i - 3] - x[i - 5]
&& x[i - 1] <= x[i - 3]
&& x[i - 2] >= x[i - 4]) {
return true;
}
if (i > 3 && x[i - 1] == x[i - 3] && x[i] >= x[i - 2] - x[i - 4]) {
return true;
}
}
return false;
}
}