제출 #972952

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
972952		sleepntsheep	Palembang Bridges (APIO15_bridge)	C11	22 / 100	43 ms	3676 KiB

bridge

#include <stdio.h>
#include <stdlib.h>
#define MAX_N 2000000

int min(int a,int b){return a<b?a:b;}
int max(int a,int b){return a>b?a:b;}
int cmpr(const void*a,const void*b){return *(const int*)a - *(const int*)b;}

int n, k, c[MAX_N<<1], p;
long long cost, pc[MAX_N<<1], z = 1e18;

int main()
{
    scanf("%d%d", &k, &n);
    for (int s, t, i = 0; i < n; ++i)
    {
        char bb, cc;
        scanf(" %c%d %c%d",&bb,&s,&cc,&t);
        if(bb==cc) cost += abs(t-s);
        else
        {
            c[++p] = s; c[++p] = t;
            ++cost;
        }
    }

    qsort(c+1, p, sizeof*c, cmpr);
    if(k==1)
    {
        for(int j=1;j<=p;++j) cost += abs(c[p/2] - c[j]);
        printf("%lld\n", cost);
        return 0;
    }

    /* partial sum on c */
    for (int i = 1; i <= p; ++i) pc[i] = pc[i-1] + c[i];

    /* some prefix of points will choose left bridge and the rest will choose right bridge
     *
     * - fix prefix and find optimal cost for that prefix
     */

    for (int i = 1; i <= p; ++i)
    {
        /* c[1..i] will use left bridge, the rest using right bridge */

        long long cost1 = 0;
        /* left bridge*/
        cost1 += (i/2ll)*c[i/2] - pc[i/2];
        cost1 += (pc[i] - pc[i/2]) - c[i/2]*1ll*(i-i/2);

        /* right bridge*/
        int j = (p-i)/2+i;
        cost1 += c[j]*1ll*(j-i) - (pc[j] - pc[i]);
        cost1 += (pc[p] - pc[j]) - c[j]*1ll*(p-j);
        if(cost1<z)z=cost1;
    }
    printf("%lld",z+cost);
}

컴파일 시 표준 에러 (stderr) 메시지

bridge.c: In function 'main':
bridge.c:14:5: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |     scanf("%d%d", &k, &n);
      |     ^~~~~~~~~~~~~~~~~~~~~
bridge.c:18:9: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |         scanf(" %c%d %c%d",&bb,&s,&cc,&t);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 14 / 14
• Subtask 3: 0 / 9
• Subtask 4: 0 / 32
• Subtask 5: 0 / 37