Given an array of intervals intervals
where intervals[i] = [starti, endi]
, return the minimum number of intervals you need to remove to make the rest of the intervals non-overlapping.
Example 1:
Input: intervals = [[1,2],[2,3],[3,4],[1,3]] Output: 1 Explanation: [1,3] can be removed and the rest of the intervals are non-overlapping.
Example 2:
Input: intervals = [[1,2],[1,2],[1,2]] Output: 2 Explanation: You need to remove two [1,2] to make the rest of the intervals non-overlapping.
Example 3:
Input: intervals = [[1,2],[2,3]] Output: 0 Explanation: You don't need to remove any of the intervals since they're already non-overlapping.
Constraints:
1 <= intervals.length <= 105
intervals[i].length == 2
-5 * 104 <= starti < endi <= 5 * 104
Greedy.
class Solution:
def eraseOverlapIntervals(self, intervals: List[List[int]]) -> int:
intervals.sort(key=lambda x: x[1])
ans, t = 0, intervals[0][1]
for s, e in intervals[1:]:
if s >= t:
t = e
else:
ans += 1
return ans
class Solution:
def eraseOverlapIntervals(self, intervals: List[List[int]]) -> int:
intervals.sort()
d = [intervals[0][1]]
for s, e in intervals[1:]:
if s >= d[-1]:
d.append(e)
else:
idx = bisect_left(d, s)
d[idx] = min(d[idx], e)
return len(intervals) - len(d)
class Solution {
public int eraseOverlapIntervals(int[][] intervals) {
Arrays.sort(intervals, Comparator.comparingInt(a -> a[1]));
int t = intervals[0][1], ans = 0;
for (int i = 1; i < intervals.length; ++i) {
if (intervals[i][0] >= t) {
t = intervals[i][1];
} else {
++ans;
}
}
return ans;
}
}
class Solution {
public int eraseOverlapIntervals(int[][] intervals) {
Arrays.sort(intervals, (a, b) -> {
if (a[0] != b[0]) {
return a[0] - b[0];
}
return a[1] - b[1];
});
int n = intervals.length;
int[] d = new int[n + 1];
d[1] = intervals[0][1];
int size = 1;
for (int i = 1; i < n; ++i) {
int s = intervals[i][0], e = intervals[i][1];
if (s >= d[size]) {
d[++size] = e;
} else {
int left = 1, right = size;
while (left < right) {
int mid = (left + right) >> 1;
if (d[mid] >= s) {
right = mid;
} else {
left = mid + 1;
}
}
d[left] = Math.min(d[left], e);
}
}
return n - size;
}
}
function eraseOverlapIntervals(intervals: number[][]): number {
intervals.sort((a, b) => a[1] - b[1]);
let end = intervals[0][1],
ans = 0;
for (let i = 1; i < intervals.length; ++i) {
let cur = intervals[i];
if (end > cur[0]) {
ans++;
} else {
end = cur[1];
}
}
return ans;
}
class Solution {
public:
int eraseOverlapIntervals(vector<vector<int>>& intervals) {
sort(intervals.begin(), intervals.end(), [](const auto& a, const auto& b) { return a[1] < b[1]; });
int ans = 0, t = intervals[0][1];
for (int i = 1; i < intervals.size(); ++i) {
if (t <= intervals[i][0])
t = intervals[i][1];
else
++ans;
}
return ans;
}
};
func eraseOverlapIntervals(intervals [][]int) int {
sort.Slice(intervals, func(i, j int) bool {
return intervals[i][1] < intervals[j][1]
})
t, ans := intervals[0][1], 0
for i := 1; i < len(intervals); i++ {
if intervals[i][0] >= t {
t = intervals[i][1]
} else {
ans++
}
}
return ans
}