제출 #910139

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
910139		nightfal	Simurgh (IOI17_simurgh)	C++14	51 / 100	91 ms	6236 KiB

simurgh

#include <cstdio>
#include <iostream>
#include <cassert>
#include <vector>
#include <cstdlib>
#include <string>
#include <utility>
#include <tuple>

using namespace std;


std::vector<int> find_roads(int n, std::vector<int> u, std::vector<int> v);
int count_common_roads(const std::vector<int>& r);

bool isSubtask1(int n) {return n<=7;}
bool isSubtask2(int n) {return n<=50;}
bool isSubtask3(int n) {return n<=240;}

void dfs3(int startNode, int startEdge, int parent, int now, vector<vector<pair<int,int>>>& edgeL, 
            vector<int>& r2, vector<int>& dNode, vector<vector<int>>& alterEdge) {
    dNode[now]=1;
    for(auto& elem: edgeL[now]) {
        int nextNode,nextEdge; tie(nextNode,nextEdge) = elem;
        if (nextNode==parent) continue;
        if (nextNode==startNode) {alterEdge[startEdge].push_back(nextEdge); continue;}
        if (!dNode[nextNode]) {
            r2.push_back(nextEdge);
            dfs3(startNode,startEdge,now,nextNode,edgeL,r2,dNode,alterEdge);
        }
    }
	return;
}
vector<int> subtask3(int n, std::vector<int>& u, std::vector<int>& v) {
    int m = u.size();
    vector<int> r;
    vector<int> treeEdge(m);
	vector<bool> testedEdge(m);

	// Edge list
    vector<vector<pair<int,int>>> edgeL(n);
    for(int i=0; i<m; i++) {
        edgeL[u[i]].push_back(make_pair(v[i],i));
        edgeL[v[i]].push_back(make_pair(u[i],i));
    }
    // printf("Edge list\n");
    // for(int i=0; i<n; i++) {printf("%d: ",i); for(auto& elem: edgeL[i]) printf("(%d,%d) ",elem.first,elem.second); printf("\n");} printf("\n");

    for(int startNode=0; startNode<n; startNode++) {
		// printf("------ startNode = %d ------\n",startNode);
        vector<int> dNode(n); vector<vector<int>> alterEdge(m);
        dNode[startNode] = 1;
        vector<int> r2, r2StartEdgeIdx;
        int secondNode,startEdge; 

        for(auto& elem: edgeL[startNode]) {
            tie(secondNode,startEdge) = elem;
            if (dNode[secondNode]) continue;
            r2.push_back(startEdge);
            r2StartEdgeIdx.push_back(r2.size()-1);
            dfs3(startNode,startEdge,startNode,secondNode,edgeL,r2,dNode,alterEdge);
        }
		
		// printf("r2: "); for(int elem: r2) printf("%d ",elem); printf("\n");
		// printf("r2StartEdgeIdx: "); for(int elem: r2StartEdgeIdx) printf("%d ",elem); printf("\n");
		// printf("alterEdge: \n"); 
		// for(int i=0; i<n; i++) { printf("%d: ",i); for(auto& elem: alterEdge[i]) printf("%d ",elem); printf("\n");}

        // int defaultCount = count_common_roads(r2);
		// tested가 있는 경우에 그것을 가지고 untested의 treeEdge 여부 계산가능

        for(int startEdgeIdx: r2StartEdgeIdx) {
            vector<int> result;
            int maxValue = -1;

            int startEdge = r2[startEdgeIdx], newStartEdge = r2[startEdgeIdx];
			vector<int> cycle; cycle.push_back(startEdge);
            for(int anEdge: alterEdge[startEdge]) cycle.push_back(anEdge);
			// printf("cycle: "); for(int elem: cycle) printf("%d ",elem); printf("\n");

			bool hasTestedEdge = false;
            for(int anEdge: cycle)
				if (testedEdge[anEdge]) {hasTestedEdge = true; newStartEdge = anEdge; break;}
			// printf("hasTestedEdge = %d, newStartEdge = %d\n",hasTestedEdge,newStartEdge);
			if (hasTestedEdge) {
				r2[startEdgeIdx] = newStartEdge;
				maxValue = count_common_roads(r2);
				if (!treeEdge[newStartEdge]) maxValue++;
				r2[startEdgeIdx] = startEdge;
			}
			// printf("maxValue = %d\n",maxValue);

            for(int anEdge: cycle) {
				int temp;
				if (testedEdge[anEdge]) { 
					temp = treeEdge[anEdge]? maxValue:maxValue-1;
				}
				else {
                	r2[startEdgeIdx] = anEdge; 
					testedEdge[anEdge] = true;
                	temp = count_common_roads(r2);
                	maxValue = max(maxValue,temp);
				}
                result.push_back(temp);
            }
			// printf("result: "); for(int elem: result) printf("%d ",elem); printf("\n");

            for(int j=0; j<result.size(); j++) 
				if (result[j] == maxValue) treeEdge[cycle[j]] = 1;
            r2[startEdgeIdx] = startEdge;        
            // printf("testedEdge: "); for(bool elem: testedEdge) printf("%d ",elem); printf("\n");
            // printf("treeEdge:   "); for(int elem: treeEdge) printf("%d ",elem); printf("\n\n");
        }
        
    }
    for(int i=0; i<m; i++) if (treeEdge[i]) r.push_back(i);
    // printf("r: "); for(int elem: r) printf("%d ",elem); printf("\n");
    return r;
}

void dfs(int parent, int now, std::vector<int>& visit, std::vector<vector<int>>& edgeL) {
    visit[now]=1;
    for(int elem: edgeL[now])
        if (elem!=parent && !visit[elem])
			dfs(now,elem,visit,edgeL);
	return;
}

bool isTree(std::vector<int>& r, std::vector<int>& u, std::vector<int>& v) {
    int n = r.size()+1;
    std::vector<vector<int>> edgeL(n);
    for(int i=0; i<n-1; i++) {
        int s = u[r[i]], e = v[r[i]];
        edgeL[s].push_back(e);
        edgeL[e].push_back(s);
    }
    vector<int> visit(n,0);
    dfs(-1,u[r[0]],visit,edgeL);
	for(int i=0; i<n; i++)
		if(!visit[i]) return false;
	return true;
}

bool selectEdges(int cnt, int start, std::vector<int>& r, std::vector<int>& u, std::vector<int>& v){
	int n = r.size()+1, m = u.size();
    if (cnt == n-1){
        if(isTree(r,u,v) && count_common_roads(r)== n-1) return true;
        else return false;
    }
    for(int i=start; i<m; i++){
        r[cnt] = i;
        if (selectEdges(cnt+1,i+1,r,u,v)) return true;
    }
    return false;
}

std::vector<int> subtask1(int n, std::vector<int>& u, std::vector<int>& v) {
    std::vector<int> r(n-1), zero(n-1,-1);
    if (selectEdges(0,0,r,u,v)) return r;
    else return zero;
}

std::vector<int> find_roads(int n, std::vector<int> u, std::vector<int> v) {
    return subtask3(n,u,v);
    // if (isSubtask1(n)) 
    return subtask1(n,u,v);
}

컴파일 시 표준 에러 (stderr) 메시지

simurgh.cpp: In function 'std::vector<int> subtask3(int, std::vector<int>&, std::vector<int>&)':
simurgh.cpp:108:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  108 |             for(int j=0; j<result.size(); j++)
      |                          ~^~~~~~~~~~~~~~
simurgh.cpp: In function 'void dfs(int, int, std::vector<int>&, std::vector<std::vector<int> >&)':
simurgh.cpp:123:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  123 |     for(int elem: edgeL[now])
      |     ^~~
simurgh.cpp:126:2: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  126 |  return;
      |  ^~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 17 / 17
• Subtask 3: 21 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30