126 lines
3.0 KiB
C
126 lines
3.0 KiB
C
/* ************************************************************************** */
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/* */
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/* ::: :::::::: */
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/* edmonds_karp.c :+: :+: :+: */
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/* +:+ +:+ +:+ */
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/* By: tmaze <tmaze@student.42.fr> +#+ +:+ +#+ */
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/* +#+#+#+#+#+ +#+ */
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/* Created: 2019/04/18 09:59:11 by tmaze #+# #+# */
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/* Updated: 2019/04/21 16:11:56 by tmaze ### ########.fr */
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/* */
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/* ************************************************************************** */
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#include "lem_in.h"
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static void go_upstream(t_lmdata *data, t_ind **path, int s_ind, t_ind *it)
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{
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int nb_nodes;
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int j;
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t_ind *it2;
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nb_nodes = 1;
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j = it->index;
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while (j != s_ind)
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{
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lst_indadd(path, j);
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nb_nodes++;
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it2 = data->adj[j];
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while (it2 && it2->weight != 2)
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it2 = it2->next;
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if (it2 && it2->weight == 2)
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j = it2->index;
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}
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(*path)->weight = nb_nodes;
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}
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static t_ind **resolve_paths(t_lmdata *data, int nb_paths, int s_ind
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, int e_ind)
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{
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t_ind **ret;
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t_ind *it;
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int i;
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if ((ret = (t_ind**)ft_memalloc(sizeof(t_ind*) * (nb_paths + 1))) != NULL)
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{
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i = 0;
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it = data->adj[e_ind];
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while (it && i < nb_paths)
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{
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if (it->weight == 2)
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{
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lst_indadd(&(ret[i]), e_ind);
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go_upstream(data, &(ret[i]), s_ind, it);
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i++;
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}
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it = it->next;
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}
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}
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return (ret);
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}
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static void update_weights(t_lmdata *data, t_bfs *tab, int s_ind, int e_ind)
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{
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int i;
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t_ind *it;
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i = e_ind;
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while (i != s_ind)
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{
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it = data->adj[i];
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while (it && it->index != tab[i].parent)
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it = it->next;
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if (it->index == tab[i].parent)
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it->weight++;
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it = data->adj[tab[i].parent];
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while (it && it->index != i)
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it = it->next;
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if (it)
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it->weight--;
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it = data->adj[i];
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while (it && it->weight == 1)
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it = it->next;
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tab[i].old_visited = (it && it->weight != 1);
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i = tab[i].parent;
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}
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}
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static void cmp_scores(t_ind ***ret, int *scores)
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{
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if (ret[0] == NULL || scores[1] < scores[0])
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{
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if (ret[0] != NULL)
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tablst_inddel(ret[0]);
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ret[0] = ret[1];
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scores[0] = scores[1];
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}
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else
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tablst_inddel(ret[1]);
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}
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t_ind **edmonds_karp(t_lmdata *data, int s_ind, int e_ind)
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{
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t_bfs tab[data->nb_nodes];
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t_ind **ret[2];
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int nb_paths;
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int scores[2];
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int i;
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ret[0] = NULL;
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scores[0] = 0;
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nb_paths = 0;
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i = 0;
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while (i < data->nb_nodes)
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tab[i++].old_visited = 0;
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bfs(data, tab, s_ind, e_ind);
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while (tab[e_ind].parent != -1)
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{
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nb_paths++;
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update_weights(data, tab, s_ind, e_ind);
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ret[1] = resolve_paths(data, nb_paths, s_ind, e_ind);
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scores[1] = get_score(data, ret[1], nb_paths);
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cmp_scores(ret, scores);
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bfs(data, tab, s_ind, e_ind);
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}
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return (ret[0]);
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}
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