Submission #7312

#	Time	Username	Problem	Language	Result	Execution time	Memory
7312		myungwoo	Ideal city (IOI12_city)	C++98	100 / 100	56 ms	9076 KiB

city

#include <vector>
#include <algorithm>
using namespace std;

#define MAXN 100005
#define MOD 1000000000
typedef long long lld;

static int N,M,V[MAXN],ans;

static struct P{
    P(){}
    P(int x,int y){ this->x=x; this->y=y; }
    int x,y;
    bool operator < (const P &ot)const{
        return y!=ot.y?y<ot.y:x<ot.x;
    }
} A[MAXN];

static struct NODE{
    int y,x1,x2;
} T[MAXN];
vector <int> con[MAXN];

inline bool cross(int a,int b,int p,int q){ return !(b < p || a > q); }
inline bool cross(const NODE &a,const NODE &b){
    if (abs(a.y-b.y) == 1 && cross(a.x1,a.x2,b.x1,b.x2)) return 1;
    return 0;
}

int dfs(int n)
{
    int i,k,cnt=T[n].x2-T[n].x1+1;
    V[n] = 1;
    for (i=con[n].size();i--;){
        k = con[n][i];
        if (V[k]) continue;
        cnt += dfs(k);
    }
    ans = (ans+lld(cnt)*(N-cnt)%MOD)%MOD;
    return cnt;
}

int proc()
{
    int i,k;
    sort(A+1,A+N+1);
    M = 0;
    for (i=k=1;i<=N;i++){ // make nodes
        if (i == N || A[i+1].y != A[i].y || A[i+1].x > A[i].x+1){
            T[++M].y = A[i].y;
            T[M].x1 = A[k].x;
            T[M].x2 = A[i].x;
            k = i+1;
        }
    }
    for (i=1;i<=M;i++) con[i].clear();
    for (i=k=1;i<=M;i++){ // make edges
        while (k < M && T[k].y < T[i].y+1 || (T[k].y == T[i].y+1 && T[k].x2 < T[i].x1)) k++;
        if (k <= M && cross(T[i],T[k])) con[i].push_back(k), con[k].push_back(i);
        while (k < M && cross(T[i],T[k+1])){
            ++k;
            con[i].push_back(k), con[k].push_back(i);
        }
    }
    ans = 0;
    for (i=1;i<=N;i++) V[i] = 0;
    dfs(1);
    return ans;
}

int DistanceSum(int n, int *x_arr, int *y_arr)
{
    int i,a,b;
    N = n;
    for (i=0;i<N;i++) A[i+1] = P(x_arr[i],y_arr[i]);
    a = proc();
    for (i=1;i<=N;i++) swap(A[i].x,A[i].y);
    b = proc();
    return (a+b)%MOD;
}

• Subtask 1: 11 / 11
• Subtask 2: 21 / 21
• Subtask 3: 23 / 23
• Subtask 4: 45 / 45