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Copy pathFindNumberK.java
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44 lines (40 loc) · 1.17 KB
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public class FindNumberK {
public int findKthLargest(int[] nums, int k) {
quickSort(nums, 0, nums.length - 1, nums.length-k);
return nums[nums.length - k];
}
private void quickSort(int[] arr, int l, int r, int k) {
if (l >= r) {
return;
}
int target = arr[l + (int) Math.random() * (r - l + 1)];
int[] border = partition(arr, l, r, target);
if(k<border[0]) {
quickSort(arr, l, border[0] - 1, k);
}
else if(k<=border[1]) return;
else {
quickSort(arr, border[1] + 1, r, k);
}
}
private int[] partition(int[] arr, int l, int r, int target) {
int less=l;
int more=r;
int index=l;
while (index <= more) {
if (arr[index] < target) {
swap(arr, less++, index++);
} else if (arr[index] == target) {
index++;
}else {
swap(arr, more--, index);
}
}
return new int[]{less, more};
}
private void swap(int[] arr, int i, int j) {
int temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
}