你打算利用空闲时间来做兼职工作赚些零花钱。
这里有 n
份兼职工作,每份工作预计从 startTime[i]
开始到 endTime[i]
结束,报酬为 profit[i]
。
给你一份兼职工作表,包含开始时间 startTime
,结束时间 endTime
和预计报酬 profit
三个数组,请你计算并返回可以获得的最大报酬。
注意,时间上出现重叠的 2 份工作不能同时进行。
如果你选择的工作在时间 X
结束,那么你可以立刻进行在时间 X
开始的下一份工作。
示例 1:
输入:startTime = [1,2,3,3], endTime = [3,4,5,6], profit = [50,10,40,70] 输出:120 解释: 我们选出第 1 份和第 4 份工作, 时间范围是 [1-3]+[3-6],共获得报酬 120 = 50 + 70。
示例 2:
输入:startTime = [1,2,3,4,6], endTime = [3,5,10,6,9], profit = [20,20,100,70,60] 输出:150 解释: 我们选择第 1,4,5 份工作。 共获得报酬 150 = 20 + 70 + 60。
示例 3:
输入:startTime = [1,1,1], endTime = [2,3,4], profit = [5,6,4] 输出:6
提示:
1 <= startTime.length == endTime.length == profit.length <= 5 * 10^4
1 <= startTime[i] < endTime[i] <= 10^9
1 <= profit[i] <= 10^4
方法一:记忆化搜索 + 二分查找
我们先将工作按照开始时间从小到大排序,然后设计一个函数
函数
对于第
其中
此过程中,我们可以使用记忆化搜索,将每个状态的答案保存下来,避免重复计算。
时间复杂度
方法二:动态规划 + 二分查找
我们还可以将方法一中的记忆化搜索改为动态规划。
先将工作排序,这次我们按照结束时间从小到大排序,然后定义
对于第
其中
时间复杂度
相似题目:
class Solution:
def jobScheduling(self, startTime: List[int], endTime: List[int], profit: List[int]) -> int:
@cache
def dfs(i):
if i >= n:
return 0
_, e, p = jobs[i]
j = bisect_left(jobs, e, lo=i + 1, key=lambda x: x[0])
return max(dfs(i + 1), p + dfs(j))
jobs = sorted(zip(startTime, endTime, profit))
n = len(profit)
return dfs(0)
class Solution:
def jobScheduling(self, startTime: List[int], endTime: List[int], profit: List[int]) -> int:
jobs = sorted(zip(endTime, startTime, profit))
n = len(profit)
dp = [0] * (n + 1)
for i, (_, s, p) in enumerate(jobs):
j = bisect_right(jobs, s, hi=i, key=lambda x: x[0])
dp[i + 1] = max(dp[i], dp[j] + p)
return dp[n]
class Solution {
private int[][] jobs;
private int[] f;
private int n;
public int jobScheduling(int[] startTime, int[] endTime, int[] profit) {
n = profit.length;
jobs = new int[n][3];
for (int i = 0; i < n; ++i) {
jobs[i] = new int[] {startTime[i], endTime[i], profit[i]};
}
Arrays.sort(jobs, (a, b) -> a[0] - b[0]);
f = new int[n];
return dfs(0);
}
private int dfs(int i) {
if (i >= n) {
return 0;
}
if (f[i] != 0) {
return f[i];
}
int e = jobs[i][1], p = jobs[i][2];
int j = search(jobs, e, i + 1);
int ans = Math.max(dfs(i + 1), p + dfs(j));
f[i] = ans;
return ans;
}
private int search(int[][] jobs, int x, int i) {
int left = i, right = n;
while (left < right) {
int mid = (left + right) >> 1;
if (jobs[mid][0] >= x) {
right = mid;
} else {
left = mid + 1;
}
}
return left;
}
}
class Solution {
public int jobScheduling(int[] startTime, int[] endTime, int[] profit) {
int n = profit.length;
int[][] jobs = new int[n][3];
for (int i = 0; i < n; ++i) {
jobs[i] = new int[] {startTime[i], endTime[i], profit[i]};
}
Arrays.sort(jobs, (a, b) -> a[1] - b[1]);
int[] dp = new int[n + 1];
for (int i = 0; i < n; ++i) {
int j = search(jobs, jobs[i][0], i);
dp[i + 1] = Math.max(dp[i], dp[j] + jobs[i][2]);
}
return dp[n];
}
private int search(int[][] jobs, int x, int n) {
int left = 0, right = n;
while (left < right) {
int mid = (left + right) >> 1;
if (jobs[mid][1] > x) {
right = mid;
} else {
left = mid + 1;
}
}
return left;
}
}
class Solution {
public:
int jobScheduling(vector<int>& startTime, vector<int>& endTime, vector<int>& profit) {
int n = profit.size();
vector<tuple<int, int, int>> jobs(n);
for (int i = 0; i < n; ++i) jobs[i] = {startTime[i], endTime[i], profit[i]};
sort(jobs.begin(), jobs.end());
vector<int> f(n);
function<int(int)> dfs = [&](int i) -> int {
if (i >= n) return 0;
if (f[i]) return f[i];
auto [_, e, p] = jobs[i];
tuple<int, int, int> t{e, 0, 0};
int j = lower_bound(jobs.begin() + i + 1, jobs.end(), t, [&](auto& l, auto& r) -> bool { return get<0>(l) < get<0>(r); }) - jobs.begin();
int ans = max(dfs(i + 1), p + dfs(j));
f[i] = ans;
return ans;
};
return dfs(0);
}
};
class Solution {
public:
int jobScheduling(vector<int>& startTime, vector<int>& endTime, vector<int>& profit) {
int n = profit.size();
vector<tuple<int, int, int>> jobs(n);
for (int i = 0; i < n; ++i) jobs[i] = {endTime[i], startTime[i], profit[i]};
sort(jobs.begin(), jobs.end());
vector<int> dp(n + 1);
for (int i = 0; i < n; ++i) {
auto [_, s, p] = jobs[i];
int j = upper_bound(jobs.begin(), jobs.begin() + i, s, [&](int x, auto& job) -> bool { return x < get<0>(job); }) - jobs.begin();
dp[i + 1] = max(dp[i], dp[j] + p);
}
return dp[n];
}
};
func jobScheduling(startTime []int, endTime []int, profit []int) int {
n := len(profit)
type tuple struct{ s, e, p int }
jobs := make([]tuple, n)
for i, p := range profit {
jobs[i] = tuple{startTime[i], endTime[i], p}
}
sort.Slice(jobs, func(i, j int) bool { return jobs[i].s < jobs[j].s })
f := make([]int, n)
var dfs func(int) int
dfs = func(i int) int {
if i >= n {
return 0
}
if f[i] != 0 {
return f[i]
}
j := sort.Search(n, func(j int) bool { return jobs[j].s >= jobs[i].e })
ans := max(dfs(i+1), jobs[i].p+dfs(j))
f[i] = ans
return ans
}
return dfs(0)
}
func max(a, b int) int {
if a > b {
return a
}
return b
}
func jobScheduling(startTime []int, endTime []int, profit []int) int {
n := len(profit)
type tuple struct{ s, e, p int }
jobs := make([]tuple, n)
for i, p := range profit {
jobs[i] = tuple{startTime[i], endTime[i], p}
}
sort.Slice(jobs, func(i, j int) bool { return jobs[i].e < jobs[j].e })
dp := make([]int, n+1)
for i, job := range jobs {
j := sort.Search(i, func(k int) bool { return jobs[k].e > job.s })
dp[i+1] = max(dp[i], dp[j]+job.p)
}
return dp[n]
}
func max(a, b int) int {
if a > b {
return a
}
return b
}