제출 #1301389

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1301389		tamir1	장애물 (IOI25_obstacles)	C++20	컴파일 에러	0 ms	0 KiB

obstacles

#include <bits/stdc++.h>
#include "obstacles.h"
using namespace std;

static int N, M;
static vector<int> Tval, Hval;
static vector<int> c;        // blocked/free
static vector<int> sum;      // prefix sum of blocked cells
static vector<int> left;     // nearest blocked to the left
static vector<int> right;    // nearest blocked to the right
static int d;                // temperature of first row

// Segment tree for range minimum query
static vector<int> seg;

// Build segment tree
void build(int node, int l, int r) {
    if (l == r) {
        seg[node] = Hval[l];
        return;
    }
    int mid = (l + r) / 2;
    build(2*node, l, mid);
    build(2*node+1, mid+1, r);
    seg[node] = min(seg[2*node], seg[2*node+1]);
}

// Query min in range [ql..qr]
int query(int node, int l, int r, int ql, int qr) {
    if (r < ql || l > qr) return INT_MAX;
    if (ql <= l && r <= qr) return seg[node];
    int mid = (l + r) / 2;
    return min(query(2*node, l, mid, ql, qr),
               query(2*node+1, mid+1, r, ql, qr));
}

void initialize(vector<int> T, vector<int> H) {
    Tval = T;
    Hval = H;
    N = Tval.size();
    M = Hval.size();

    d = Tval[0];   // first row temperature

    c.assign(M, 0);
    sum.assign(M, 0);
    left.assign(M, -1);
    right.assign(M, M);

    for (int i = 0; i < M; i++)
        c[i] = (Hval[i] >= d);  // blocked if Hval >= d

    // prefix sum of blocked cells
    sum[0] = c[0];
    for (int i = 1; i < M; i++)
        sum[i] = sum[i-1] + c[i];

    // nearest blocked to the right
    int last = M;
    for (int i = M-1; i >= 0; i--) {
        if (c[i]) last = i;
        else right[i] = last - 1;
    }

    // nearest blocked to the left
    last = -1;
    for (int i = 0; i < M; i++) {
        if (c[i]) last = i;
        else left[i] = last + 1;
    }

    // build segment tree for Hval
    seg.assign(4*M, INT_MAX);
    build(1, 0, M-1);
}

bool can_reach(int L, int R, int S, int D) {
    if (S > D) swap(S, D);

    int min_in_range = query(1, 0, M-1, S, D);

    // If temperature > max humidity in the path, llama can go
    if (d > min_in_range) return true;

    // Also check if prefix sums indicate fully free path
    int blocked = sum[D] - (S > 0 ? sum[S-1] : 0);
    if (blocked == 0) return true;

    return false;
}

컴파일 시 표준 에러 (stderr) 메시지

obstacles.cpp: In function 'void initialize(std::vector<int>, std::vector<int>)':
obstacles.cpp:47:5: error: reference to 'left' is ambiguous
   47 |     left.assign(M, -1);
      |     ^~~~
In file included from /usr/include/c++/13/streambuf:43,
                 from /usr/include/c++/13/bits/streambuf_iterator.h:35,
                 from /usr/include/c++/13/iterator:66,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:54,
                 from obstacles.cpp:1:
/usr/include/c++/13/bits/ios_base.h:1042:3: note: candidates are: 'std::ios_base& std::left(ios_base&)'
 1042 |   left(ios_base& __base)
      |   ^~~~
obstacles.cpp:9:20: note:                 'std::vector<int> left'
    9 | static vector<int> left;     // nearest blocked to the left
      |                    ^~~~
obstacles.cpp:48:5: error: reference to 'right' is ambiguous
   48 |     right.assign(M, M);
      |     ^~~~~
/usr/include/c++/13/bits/ios_base.h:1050:3: note: candidates are: 'std::ios_base& std::right(ios_base&)'
 1050 |   right(ios_base& __base)
      |   ^~~~~
obstacles.cpp:10:20: note:                 'std::vector<int> right'
   10 | static vector<int> right;    // nearest blocked to the right
      |                    ^~~~~
obstacles.cpp:62:14: error: reference to 'right' is ambiguous
   62 |         else right[i] = last - 1;
      |              ^~~~~
/usr/include/c++/13/bits/ios_base.h:1050:3: note: candidates are: 'std::ios_base& std::right(ios_base&)'
 1050 |   right(ios_base& __base)
      |   ^~~~~
obstacles.cpp:10:20: note:                 'std::vector<int> right'
   10 | static vector<int> right;    // nearest blocked to the right
      |                    ^~~~~
obstacles.cpp:69:14: error: reference to 'left' is ambiguous
   69 |         else left[i] = last + 1;
      |              ^~~~
/usr/include/c++/13/bits/ios_base.h:1042:3: note: candidates are: 'std::ios_base& std::left(ios_base&)'
 1042 |   left(ios_base& __base)
      |   ^~~~
obstacles.cpp:9:20: note:                 'std::vector<int> left'
    9 | static vector<int> left;     // nearest blocked to the left
      |                    ^~~~