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Java Solution for LeetCode algorithm problems, continually updating
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package g0701_0800.s0735_asteroid_collision;
// #Medium #Array #Stack #Level_2_Day_18_Stack #2022_03_25_Time_2_ms_(99.59%)_Space_43.1_MB_(91.77%)
import java.util.Deque;
import java.util.LinkedList;
public class Solution {
public int[] asteroidCollision(int[] asteroids) {
Deque stack = new LinkedList<>();
for (int a : asteroids) {
if (a > 0) {
stack.addLast(a);
} else {
if (!stack.isEmpty() && stack.peekLast() > 0) {
if (stack.peekLast() == Math.abs(a)) {
stack.pollLast();
} else {
while (!stack.isEmpty()
&& stack.peekLast() > 0
&& stack.peekLast() < Math.abs(a)) {
stack.pollLast();
}
if (!stack.isEmpty()
&& stack.peekLast() > 0
&& stack.peekLast() == Math.abs(a)) {
stack.pollLast();
} else if (stack.isEmpty() || stack.peekLast() < 0) {
stack.addLast(a);
}
}
} else {
stack.addLast(a);
}
}
}
int[] ans = new int[stack.size()];
for (int i = stack.size() - 1; i >= 0; i--) {
ans[i] = stack.pollLast();
}
return ans;
}
}