算法训练营day31,贪心算法5
package main
import (
"fmt"
"sort"
)
//435. 无重叠区间
func eraseOverlapIntervals(intervals [][]int) int {
if len(intervals) == 0 {
return 0
}
count := 0 //移除数量
//按第一位从小到大排序
sort.Slice(intervals, func(i, j int) bool {
return intervals[i][0] < intervals[j][0]
})
for i := 1; i < len(intervals); i++ {
//如果当前左边界比前一个右边界比小，说明重叠需要删除
if intervals[i][0] < intervals[i-1][1] {
count++
if intervals[i][1] > intervals[i-1][1] {
intervals[i][1] = intervals[i-1][1]
}
}
}
return count
}
//763. 划分字母区间
func partitionLabels(s string) []int {
m1 := make(map[byte]int)
for i := 0; i < len(s); i++ {
m1[s[i]] = i
}
result := make([]int, 0)
left, right := 0, 0
for i := 0; i < len(s); i++ {
if m1[s[i]] > right {
right = m1[s[i]]
}
if i == right {
result = append(result, right-left+1)
left = i + 1
}
}
return result
}
//56. 合并区间
func merge(intervals [][]int) [][]int {
result := make([][]int, 0)
sort.Slice(intervals, func(i, j int) bool {
return intervals[i][0] < intervals[j][0]
})
result = append(result, intervals[0])
for i := 1; i < len(intervals); i++ {
//如果当前左边界比结果数组最后一个右边界比小，说明重叠
if intervals[i][0] <= intervals[i-1][1] {
if result[len(result)-1][1] < intervals[i][1] {
result[len(result)-1][1] = intervals[i][1]
}
} else {
result = append(result, intervals[i])
}
}
return result
}