g2101_2200.s2126_destroying_asteroids.Solution Maven / Gradle / Ivy
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Java Solution for LeetCode algorithm problems, continually updating
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package g2101_2200.s2126_destroying_asteroids;
// #Medium #Array #Sorting #Greedy #2022_06_08_Time_6_ms_(99.27%)_Space_54.1_MB_(97.81%)
public class Solution {
public boolean asteroidsDestroyed(int mass, int[] asteroids) {
return helper(mass, 0, asteroids);
}
private boolean helper(long mass, int startIndex, int[] asteroids) {
int smallOrEqualIndex = partition(mass, startIndex, asteroids);
if (smallOrEqualIndex < startIndex) {
return false;
}
if (smallOrEqualIndex >= asteroids.length - 1) {
return true;
}
for (int i = startIndex; i <= smallOrEqualIndex; ++i) {
mass += asteroids[i];
}
return helper(mass, ++smallOrEqualIndex, asteroids);
}
private int partition(long mass, int startIndex, int[] asteroids) {
int length = asteroids.length;
int smallOrEqualIndex = startIndex - 1;
for (int i = startIndex; i < length; ++i) {
if (asteroids[i] <= mass) {
smallOrEqualIndex++;
swap(asteroids, i, smallOrEqualIndex);
}
}
return smallOrEqualIndex;
}
private void swap(int[] array, int i, int j) {
int tmp = array[i];
array[i] = array[j];
array[j] = tmp;
}
}