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1723:完成所有工作的最短时间

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huangge1199 2021-05-08 12:15:32 +08:00
parent 6cfe32c5f8
commit 2be3e98b33
1 changed files with 73 additions and 22 deletions
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95
src/main/java/leetcode/editor/cn/FindMinimumTimeToFinishAllJobs.java
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@ -38,7 +38,9 @@
package leetcode.editor.cn; package leetcode.editor.cn;
import java.lang.reflect.Array;
import java.util.ArrayList; import java.util.ArrayList;
import java.util.Arrays;
import java.util.List; import java.util.List;
//1723:完成所有工作的最短时间 //1723:完成所有工作的最短时间
@ -56,35 +58,84 @@ public class FindMinimumTimeToFinishAllJobs {
//leetcode submit region begin(Prohibit modification and deletion) //leetcode submit region begin(Prohibit modification and deletion)
class Solution { class Solution {
// public int minimumTimeRequired(int[] jobs, int k) {
// List<Integer> list = new ArrayList<>();
// return dfs(0, 0, list, 0, Integer.MAX_VALUE, jobs, k);
// }
//
// int dfs(int index, int kIndex, List<Integer> list, int max, int ans, int[] jobs, int k) {
// if (kIndex < k) {
// list.add(kIndex, jobs[index]);
// if (Math.max(list.get(kIndex), max) < ans) {
// if (index == jobs.length - 1) {
// ans = Math.max(list.get(kIndex), max);
// } else {
// ans = dfs(index + 1, kIndex + 1, list, Math.max(list.get(kIndex), max), ans, jobs, k);
// }
// }
// list.add(kIndex, 0);
// }
// for (int i = 0; i < kIndex; i++) {
// list.set(i, list.get(i) + jobs[index]);
// if (Math.max(list.get(i), max) < ans) {
// if (index == jobs.length - 1) {
// ans = Math.max(list.get(i), max);
// } else {
// ans = dfs(index + 1, kIndex, list, Math.max(list.get(i), max), ans, jobs, k);
// }
// }
// list.set(i, list.get(i) - jobs[index]);
// }
// return ans;
// }
public int minimumTimeRequired(int[] jobs, int k) { public int minimumTimeRequired(int[] jobs, int k) {
List<Integer> list = new ArrayList<>(); Arrays.sort(jobs);
return dfs(0, 0, list, 0, Integer.MAX_VALUE, jobs, k); int low = 0, high = jobs.length - 1;
while (low < high) {
int temp = jobs[low];
jobs[low] = jobs[high];
jobs[high] = temp;
low++;
high--;
}
int l = jobs[0], r = Arrays.stream(jobs).sum();
while (l < r) {
int mid = (l + r) >> 1;
if (check(jobs, k, mid)) {
r = mid;
} else {
l = mid + 1;
}
}
return l;
} }
int dfs(int index, int kIndex, List<Integer> list, int max, int ans, int[] jobs, int k) { public boolean check(int[] jobs, int k, int limit) {
if (kIndex < k) { int[] workloads = new int[k];
list.add(kIndex, jobs[index]); return backtrack(jobs, workloads, 0, limit);
if (Math.max(list.get(kIndex), max) < ans) { }
if (index == jobs.length - 1) {
ans = Math.max(list.get(kIndex), max); public boolean backtrack(int[] jobs, int[] workloads, int i, int limit) {
} else { if (i >= jobs.length) {
ans = dfs(index + 1, kIndex + 1, list, Math.max(list.get(kIndex), max), ans, jobs, k); return true;
}
}
list.add(kIndex, 0);
} }
for (int i = 0; i < kIndex; i++) { int cur = jobs[i];
list.set(i, list.get(i) + jobs[index]); for (int j = 0; j < workloads.length; ++j) {
if (Math.max(list.get(i), max) < ans) { if (workloads[j] + cur <= limit) {
if (index == jobs.length - 1) { workloads[j] += cur;
ans = Math.max(list.get(i), max); if (backtrack(jobs, workloads, i + 1, limit)) {
} else { return true;
ans = dfs(index + 1, kIndex, list, Math.max(list.get(i), max), ans, jobs, k);
} }
workloads[j] -= cur;
}
// 如果当前工人未被分配工作，那么下一个工人也必然未被分配工作
// 或者当前工作恰能使该工人的工作量达到了上限
// 这两种情况下我们无需尝试继续分配工作
if (workloads[j] == 0 || workloads[j] + cur == limit) {
break;
} }
list.set(i, list.get(i) - jobs[index]);
} }
return ans; return false;
} }
} }
//leetcode submit region end(Prohibit modification and deletion) //leetcode submit region end(Prohibit modification and deletion)