107 lines
2.1 KiB
C++
107 lines
2.1 KiB
C++
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#include <bits/stdc++.h>
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using namespace std;
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const int N = 500, OO = 1e9;
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int dist[N][N];
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//Initialize the distance matrix with infinities to indicate that there is no edge between nodes
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void initialize_dist(int n) {
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for (int i = 0; i < n; i++) {
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for (int j = 0; j < n; j++) {
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dist[i][j] = OO;
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if (i == j) {
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dist[i][j] = 0;
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}
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}
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}
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}
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//Take Edge input and update the distance matrix
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void input(int m) {
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for (int i = 0; i < m; i++) {
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int a, b, c;
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cin >> a >> b >> c;
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dist[a][b] = c;
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dist[b][a] = c;
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}
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}
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//Perform Floyd-Warshall algorithm to calculate all shortest paths
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int floyd(int n) {
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for (int k = 0; k < n; k++) {
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for (int i = 0; i < n; i++) {
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for (int j = 0; j < n; j++) {
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if (dist[i][j] > dist[i][k] + dist[k][j]) {
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dist[i][j] = dist[i][k] + dist[k][j];
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}
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}
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}
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}
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}
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//Take queries and output the shortest distance for each query
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void output(int q) {
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for (int i = 0; i < q; i++) {
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int x, y;
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cin >> x >> y;
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cout << dist[x][y] << endl;
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}
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}
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int main() {
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int n, m, q;
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cin >> n; // Number of nodes
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initialize_dist(n);
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cin >> m; // Number of edges
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input(m);
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floyd(n);
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cin >> q; // Number of queries
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output(q);
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return 0;
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}
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/*
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Time Complexity: O(n^3)
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Memory Complexity: O(n^2)
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*/
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/*
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Example:
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5 // Number of nodes
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10 // Number of edges
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0 1 5 // Edge from Node 0 to Node 1 with Weight 5
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0 2 3
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0 3 4
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0 4 1
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1 2 4
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1 3 1
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1 4 1
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2 3 1
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2 4 2
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3 4 4
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10 // Number of Queries
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0 1 // Print Minimum Path between Nodes 0 and 1
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0 2
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0 3
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0 4
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1 2
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1 3
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1 4
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2 3
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2 4
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3 4
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Output:
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2 //Minimum path from 0 to 1
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3 //Minimum path from 0 to 2
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3 //Minimum path from 0 to 3
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1 //Minimum path from 0 to 4
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2 //Minimum path from 1 to 2
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1 //Minimum path from 1 to 3
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1 //Minimum path from 1 to 4
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1 //Minimum path from 2 to 3
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2 //Minimum path from 2 to 4
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2 //Minimum path from 3 to 4
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*/
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