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// 1791. Find Center of Star Graph
#include "leetcode.h"
/*
* there is an undirected star graph consisting of 'n' nodes labeled from 1 to
* 'n'. a star graph is a graph where there is one centre node and exactly 'n -
* 1' edges that connect the centre node with every other node. you are given a
* 2d integer array 'edges' where 'edges[i] = [ui, vi]' indicates that there is
* an edge between the node 'ui' and 'vi'. return the centre of the star graph.
*/
int findCenter(int **edges, int edgesSize, int *edgesColSize) {
int centre = 0, col = 0, candidate = edges[0][col], n = 0;
for (int i = 0; i < edgesSize; i++) {
for (int j = 0; j < edgesColSize[i]; j++)
if (candidate == edges[i][j]) {
centre = edges[i][j];
n++;
}
if (i == edgesSize - 1 && n < edgesSize) {
i = 0;
candidate = edges[0][col + 1];
}
}
return centre;
}
int main() {
int e1[3][2] = {{1, 2}, {2, 3}, {4, 2}},
e2[4][2] = {{1, 2}, {5, 1}, {1, 3}, {1, 4}};
int ecs1 = 3, ecs2 = 4;
printf("%d\n", findCenter((int **)e1, ARRAY_SIZE(e1), &ecs1)); // expect: 2
printf("%d\n", findCenter((int **)e2, ARRAY_SIZE(e2), &ecs2)); // expect: 1
}
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