算法记录Day 26 | 回溯算法part03
LeetCode 39. 组合总和
题目链接：39. 组合总和
题解
func combinationSum(candidates []int, target int) [][]int {
result := make([][]int, 0)
dfs39(candidates, 0, target, 0, []int{}, &result)
return result
}
func dfs39(candidates []int, start int, target int, sum int, path []int, result *[][]int) {
if sum > target {
return
}
if sum == target {
temp := make([]int, len(path))
copy(temp, path)
*result = append(*result, temp)
return
}
for i := start; i < len(candidates); i++ {
path = append(path, candidates[i])
sum += candidates[i]
dfs39(candidates, i, target, sum, path, result)
path = path[:len(path)-1]
sum -= candidates[i]
}
}
LeetCode 40.组合总和II
题目链接：40. 组合总和 II
题解
import "sort"
func combinationSum2(candidates []int, target int) [][]int {
result := make([][]int, 0)
used := make([]bool, len(candidates))
sort.Ints(candidates)
dfs40(candidates, 0, target, 0, used, []int{}, &result)
return result
}
func dfs40(candidates []int, start int, target int, sum int, used []bool, path []int, result *[][]int) {
if sum == target {
temp := make([]int, len(path))
copy(temp, path)
*result = append(*result, temp)
return
}
for i := start; i < len(candidates); i++ {
if sum+candidates[i] > target {
break
}
if i > 0 && candidates[i] == candidates[i-1] && !used[i-1] {
continue
}
sum += candidates[i]
path = append(path, candidates[i])
used[i] = true
dfs40(candidates, i+1, target, sum, used, path, result)
sum -= candidates[i]
path = path[:len(path)-1]
used[i] = false
}
}
LeetCode 131.分割回文串
题目链接：131. 分割回文串
题解
func partition(s string) [][]string {
result := make([][]string, 0)
dfs131(s, 0, []string{}, &result)
return result
}
func dfs131(s string, start int, path []string, result *[][]string) {
if start == len(s) {
temp := make([]string, len(path))
copy(temp, path)
*result = append(*result, temp)
return
}
for i := start; i < len(s); i++ {
if isPair(s, start, i) {
path = append(path, s[start:i+1])
dfs131(s, i+1, path, result)
path = path[:len(path)-1]
}
}
}
func isPair(s string, start int, end int) bool {
for start < end {
if s[start] != s[end] {
return false
}
start++
end--
}
return true
}
