Submission #1758111

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Source Code Expand

#include <stdio.h>
#include <stdlib.h>
#define tree_valtype int
typedef struct tree_edge_sub tree_edge;

typedef struct {
	int num;
	int nearnum;
	tree_edge *near;
}tree_vertex_sub;

struct tree_edge_sub{
	tree_vertex_sub *v;
	int w;
	tree_edge *next;
};

typedef struct tree_v_sub tree_vertex;

struct tree_v_sub{
	int num;
	tree_valtype val;
	tree_vertex *parent;
	int pareweight;
	int chilnum;
	tree_vertex **children;
	int *chilweight;
};

typedef struct {
	int N;
	int root;
	tree_vertex_sub **v_s;
	tree_vertex **v;
	tree_vertex **sorted_v;
}tree;

//頂点数N, 根の番号root, 各頂点の初期値ini_valの木を作る
tree *make_tree(int N, int root, tree_valtype ini_val){
	int i;
	tree *t = (tree *)malloc(sizeof(tree));
	t->N = N;
	t->root = root;
	t->v_s = (tree_vertex_sub **)malloc(sizeof(tree_vertex_sub *) * N);
	t->v = (tree_vertex **)malloc(sizeof(tree_vertex *) * N);
	t->sorted_v = (tree_vertex **)malloc(sizeof(tree_vertex *) * N);
	tree_vertex *parent_in_law = (tree_vertex *)malloc(sizeof(tree_vertex));
	parent_in_law->num = -1;
	parent_in_law->val = ini_val;
	parent_in_law->parent = NULL;
	parent_in_law->pareweight = -1;
	parent_in_law->chilnum = 0;
	parent_in_law->children = NULL;
	parent_in_law->chilweight = NULL;
	for(i = 0; i < N; i++){
		(t->v_s)[i] = (tree_vertex_sub *)malloc(sizeof(tree_vertex_sub));
		(t->v_s)[i]->num = i;
		(t->v_s)[i]->nearnum = 0;
		(t->v_s)[i]->near = NULL;
		(t->v)[i] = (tree_vertex *)malloc(sizeof(tree_vertex));
		(t->v)[i]->num = i;
		(t->v)[i]->val = ini_val;
		(t->v)[i]->parent = parent_in_law;
		(t->v)[i]->pareweight = -1;
		(t->v)[i]->chilnum = 0;
		(t->v)[i]->children = NULL;
		(t->v)[i]->chilweight = NULL;
		(t->sorted_v)[i] = NULL;
	}
	return t;
}

//木tの頂点aと頂点bの間に重みwの無向辺を張る (0 <= a, b <= N - 1)
void set_edge_tree(int a, int b, int w, tree *t){
	tree_edge *new1 = (tree_edge *)malloc(sizeof(tree_edge));
	new1->v = (t->v_s)[b];
	new1->w = w;
	new1->next = (t->v_s)[a]->near;
	(t->v_s)[a]->near = new1;
	(t->v_s)[a]->nearnum++;

	tree_edge *new2 = (tree_edge *)malloc(sizeof(tree_edge));
	new2->v = (t->v_s)[a];
	new2->w = w;
	new2->next = (t->v_s)[b]->near;
	(t->v_s)[b]->near = new2;
	(t->v_s)[b]->nearnum++;
}

//set_edge_tree後に呼び出す
void build_tree(tree *t){
	int i, j;
	tree_vertex_sub **v_s = t->v_s;
	tree_vertex **v = t->v;
	tree_vertex **sorted_v = t->sorted_v;
	sorted_v[0] = v[t->root];
	tree_vertex *nowv;
	tree_edge *nowe;
	for(i = 0, j = 1; j - i > 0; i++){
		nowv = sorted_v[i];
		if(i == 0){
			v_s[nowv->num]->nearnum++;
		}
		nowv->children = (tree_vertex **)malloc(sizeof(tree_vertex *) * (v_s[nowv->num]->nearnum - 1));
		nowv->chilweight = (int *)malloc(sizeof(int) * (v_s[nowv->num]->nearnum - 1));
		if(i == 0){
			v_s[nowv->num]->nearnum--;
		}
		for(nowe = v_s[nowv->num]->near; nowe != NULL; nowe = nowe->next){
			if(nowe->v->num != nowv->parent->num){
				(nowv->children)[nowv->chilnum] = v[nowe->v->num];
				(nowv->chilweight)[nowv->chilnum] = nowe->w;
				nowv->chilnum++;
				v[nowe->v->num]->parent = nowv;
				v[nowe->v->num]->pareweight = nowe->w;
				sorted_v[j] = v[nowe->v->num];
				j++;
			}
		}
	}
}
typedef struct {
	int all_ancestor_num;
	int ancestor_num;
	tree_vertex **ancestors;
}data_LCA;

int digit_count(int n){
	int ans;
	for(ans = -1; n != 0; ans++){
		n >>= 1;
	}
	return ans;
}

data_LCA **reserve_LCA(tree *t){
	int N = t->N, i, j;
	data_LCA **datas = (data_LCA **)malloc(sizeof(data_LCA *) * N);
	tree_vertex *nowv;
	data_LCA *nowdata;
	nowv = t->sorted_v[0];
	datas[nowv->num] = (data_LCA *)malloc(sizeof(data_LCA));
	nowdata = datas[nowv->num];
	nowdata->all_ancestor_num = 0;
	nowdata->ancestor_num = 0;
	nowdata->ancestors = NULL;
	for(i = 1; i < N; i++){
		nowv = t->sorted_v[i];
		datas[nowv->num] = (data_LCA *)malloc(sizeof(data_LCA));
		nowdata = datas[nowv->num];
		nowdata->all_ancestor_num = datas[nowv->parent->num]->all_ancestor_num + 1;
		nowdata->ancestor_num = digit_count(nowdata->all_ancestor_num) + 1;
		nowdata->ancestors = (tree_vertex **)malloc(sizeof(tree_vertex *) * nowdata->ancestor_num);
		nowdata->ancestors[0] = nowv->parent;
		for(j = 1; j < nowdata->ancestor_num; j++){
			nowdata->ancestors[j] = datas[nowdata->ancestors[j - 1]->num]->ancestors[j - 1];
		}
	}
	return datas;
}

//2つの頂点番号a,bとreserve_LCAで生成したdatasを受け取りaとbのLCA(最小共通祖先)の頂点番号を返す
int LCA(int a, int b, data_LCA **datas){
	int tmp, i;
	if(datas[a]->all_ancestor_num < datas[b]->all_ancestor_num){
		tmp = a;
		a = b;
		b = tmp;
	}
	for(i = datas[a]->ancestor_num - 1; i >= 0 && datas[a]->ancestor_num > 0; i--){
		while(i >= datas[a]->ancestor_num){
			i--;
		}
		if(datas[datas[a]->ancestors[i]->num]->all_ancestor_num >= datas[b]->all_ancestor_num){
			a = datas[a]->ancestors[i]->num;
		}
	}
	if(a == b){
		return a;
	}
	else{
		for(i = datas[a]->ancestor_num - 1; i >= 0; i--){
			while(i >= datas[a]->ancestor_num){
				i--;
			}
			if(datas[a]->ancestors[i] != datas[b]->ancestors[i]){
				a = datas[a]->ancestors[i]->num;
				b = datas[b]->ancestors[i]->num;
			}
		}
		return datas[a]->ancestors[0]->num;
	}
}

int main(){
	int N, x, y, Q, a, b, i;
	scanf("%d", &N);
	tree *t = make_tree(N, 0, 0);
	for(i = 1; i < N; i++){
		scanf("%d%d", &x, &y);
		set_edge_tree(x - 1, y - 1, 0, t);
	}
	build_tree(t);
	data_LCA **datas = reserve_LCA(t);
	scanf("%d", &Q);
	int *ans = (int *)malloc(sizeof(int) * Q);
	for(i = 0; i < Q; i++){
		scanf("%d%d", &a, &b);
		a--;
		b--;
		ans[i] = datas[a]->all_ancestor_num + datas[b]->all_ancestor_num - 2 * datas[LCA(a, b, datas)]->all_ancestor_num + 1;
	}
	for(i = 0; i < Q; i++){
		printf("%d\n", ans[i]);
	}
	return 0;
}

Submission Info

Compile Error

./Main.c: In function ‘main’:
./Main.c:197:2: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
  ^
./Main.c:200:3: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &x, &y);
   ^
./Main.c:205:2: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &Q);
  ^
./Main.c:208:3: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a, &b);
   ^

Judge Result