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kkunkka
2023-12-11 18:09:05 +08:00
parent 4ccaaa2885
commit 199895132f
1 changed files with 173 additions and 53 deletions
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226
src/main/java/com/dota/graph/Solution.java
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@@ -4,67 +4,187 @@ import java.util.*;
class Solution { class Solution {
long res = 0; long res = 0;
int sum = 0; int sum = 0;
public long minimumFuelCost(int[][] roads, int seats) { public long minimumFuelCost(int[][] roads, int seats) {
List<Integer>[] map = new List[roads.length + 1]; List<Integer>[] map = new List[roads.length + 1];
for (int i = 0; i < map.length; i++) { for (int i = 0; i < map.length; i++) {
map[i] = new ArrayList<>(); map[i] = new ArrayList<>();
} }
for (int[] road : roads) { for (int[] road : roads) {
map[road[0]].add(road[1]); map[road[0]].add(road[1]);
map[road[1]].add(road[0]); map[road[1]].add(road[0]);
} }
dfs(0, -1, seats, map); dfs(0, -1, seats, map);
return res; return res;
} }
int dfs(int start, int from, int seats, List<Integer>[] map) { int dfs(int start, int from, int seats, List<Integer>[] map) {
int cur = 1; int cur = 1;
for (Integer i : map[start]) { for (Integer i : map[start]) {
if (i != from) { if (i != from) {
int childSum = dfs(i, start, seats, map); int childSum = dfs(i, start, seats, map);
cur += childSum; cur += childSum;
res += (childSum + seats - 1) / seats; res += (childSum + seats - 1) / seats;
} }
} }
return cur; return cur;
} }
// 1466. 重新规划路线 // 1466. 重新规划路线
public int minReorder(int n, int[][] connections) { public int minReorder(int n, int[][] connections) {
List<Integer>[] list = new List[n]; List<Integer>[] list = new List[n];
List<Integer>[] otherList = new List[n]; List<Integer>[] otherList = new List[n];
for (int i = 0; i < list.length; i++) { for (int i = 0; i < list.length; i++) {
list[i] = new ArrayList<>(); list[i] = new ArrayList<>();
otherList[i] = new ArrayList<>(); otherList[i] = new ArrayList<>();
} }
for (int[] ints : connections) { for (int[] ints : connections) {
list[ints[0]].add(ints[1]); list[ints[0]].add(ints[1]);
otherList[ints[1]].add(ints[0]); otherList[ints[1]].add(ints[0]);
} }
dfs(0, -1, list, otherList); dfs(0, -1, list, otherList);
return sum; return sum;
} }
private void dfs(int now, int parent, List<Integer>[] list, List<Integer>[] otherList) { private void dfs(int now, int parent, List<Integer>[] list, List<Integer>[] otherList) {
for (int i = 0; i < list[now].size(); i++) { for (int i = 0; i < list[now].size(); i++) {
if (list[now].get(i) != parent) { if (list[now].get(i) != parent) {
sum++; sum++;
dfs(list[now].get(i), now, list, otherList); dfs(list[now].get(i), now, list, otherList);
} }
} }
for (int i = 0; i < otherList[now].size(); i++) { for (int i = 0; i < otherList[now].size(); i++) {
if (otherList[now].get(i) != parent) { if (otherList[now].get(i) != parent) {
dfs(otherList[now].get(i), now, list, otherList); dfs(otherList[now].get(i), now, list, otherList);
} }
} }
} }
int min = Integer.MAX_VALUE;
int N = 10001;
int[] union = new int[N];
int find(int x) {
while (union[x] != x) {
union[x] = union[union[x]];
x = union[x];
}
return x;
}
// 使用并查集
public int minimumEffortPath(int[][] heights) {
for (int i = 0; i < N; i++) {
union[i] = i;
}
int n = heights.length;
int m = heights[0].length;
List<int[]> list = new ArrayList<>(1000001);
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
int idx = index(i, j, n, m);
int i1 = index(i, j + 1, n, m);
int i2 = index(i + 1, j, n, m);
if (i1 != -1) {
int hei = Math.abs(heights[i][j]-heights[i][j+1]);
list.add(new int[]{idx, i1, hei});
}
if (i2 != -1) {
int hei = Math.abs(heights[i][j]-heights[i+1][j]);
list.add(new int[]{idx, i2, hei});
}
}
}
for (int[] ints : list) {
union[find(ints[0])] = find(ints[1]);
if (find(0)==find(n*m-1)) {
return ints[2];
}
}
return 0;
}
int index(int i, int j, int n, int m) {
if (i < 0 || j < 0 || i >= n || j >= m) {
return -1;
}
return (i * m) + j;
}
} }
class Solution1 {
private int[] parent;
private Edge[] edges = new Edge[1000001];
public int minimumEffortPath(int[][] heights) {
int m = heights.length, n = heights[0].length;
if (m == 1 && n == 1) return 0;
parent = new int[m * n];
for (int i = 0; i < m * n; i++) parent[i] = i;
int min = Integer.MAX_VALUE, max = Integer.MIN_VALUE;
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
if (i < m-1) {
int diff = Math.abs(heights[i][j] - heights[i+1][j]);
edges[diff] = new Edge(i * n + j, (i+1) * n + j, edges[diff]);
if(diff > max) max = diff;
if(diff < min) min = diff;
}
if (j < n-1) {
int diff = Math.abs(heights[i][j] - heights[i][j+1]);
edges[diff] = new Edge(i * n + j, i * n + (j+1), edges[diff]);
if(diff > max) max = diff;
if(diff < min) min = diff;
}
}
}
for(int i = min; i <= max; ++i){
for (Edge e = edges[i]; e != null; e = e.next) {
int xParent = find(e.x, parent), yParent = find(e.y, parent);
parent[xParent] = yParent;
if (find(0, parent) == find(m * n -1, parent)) return i;
}
}
return 0;
}
private int find(int x, int[] parent) {
while (parent[x] != x) {
parent[x] = parent[parent[x]];
x = parent[x];
}
return x;
}
class Edge {
int x, y;
Edge next;
Edge(int x, int y, Edge next) {
this.x = x;
this.y = y;
this.next = next;
}
}
}