js实现kruskal和prim算法

1.kruskal算法

const INF = Number.MAX_SAFE_INTEGER;
const find = (i, parent) => {
  while (parent[i]) {
    i = parent[i]; // eslint-disable-line prefer-destructuring
  }
  return i;
};
const union = (i, j, parent) => {
  if (i !== j) {
    parent[j] = i;
    return true;
  }
  return false;
};
const initializeCost = graph => {
  const cost = [];
  const { length } = graph;
  for (let i = 0; i < length; i++) {
    cost[i] = [];
    for (let j = 0; j < length; j++) {
      if (graph[i][j] === 0) {
        cost[i][j] = INF;
      } else {
        cost[i][j] = graph[i][j];
      }
    }
  }
  return cost;
};
export const kruskal = graph => {
  const { length } = graph;
  const parent = [];
  let ne = 0;
  let a;
  let b;
  let u;
  let v;
  const cost = initializeCost(graph);
  while (ne < length - 1) {
    for (let i = 0, min = INF; i < length; i++) {
      for (let j = 0; j < length; j++) {
        if (cost[i][j] < min) {
          min = cost[i][j];
          a = u = i;
          b = v = j;
        }
      }
    }
    u = find(u, parent);
    v = find(v, parent);
    if (union(u, v, parent)) {
      ne++;
    }
    cost[a][b] = cost[b][a] = INF;
  }
  return parent;
};

2.prim算法

var graph = [
    [0, 2, 4, 0, 0, 0],
    [2, 0, 2, 4, 2, 0],
    [4, 2, 0, 0, 3, 0],
    [0, 4, 0, 0, 3, 2],
    [0, 2, 3, 3, 0, 2],
    [0, 0, 0, 2, 2, 0]
]
function prime(graph,src){
    const dist = [];
    const visited = [];
    const parent = [];
    const {length} = graph;
    const INF = Number.MAX_SAFE_INTEGER;

    for(let i = 0; i < length; i++){
        dist[i] = INF;
        visited[i] = false;
       
    }
    dist[src] = 0;
    parent[src] = -1;
    let index = 0;
    while(index < length-1){
        let currentEdge = graph[src];
        visited[src] = true;
        for(let i = 0; i <currentEdge.length; i++){
            if(currentEdge[i]!==0){
                if(currentEdge[i]<dist[i]){
                    dist[i] = currentEdge[i];
                    parent[i] = src;
                }
            }
        }
        let min = INF;
        let minIndex = -1;
        for(let i = 0; i < dist.length; i++){
            if(!visited[i] && dist[i] < min){
                min = dist[i];
                minIndex = i;
            }
        }
        src = minIndex;
        index++;
    }
    return parent;
}
console.log(prime(graph,0));
原文地址:https://www.cnblogs.com/MySweetheart/p/13444993.html