Submission #723756

#	Time	Username	Problem	Language	Result	Execution time	Memory
723756		drdilyor	Worm Worries (BOI18_worm)	C++17	0 / 100	4 ms	4212 KiB

worm

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

int query(int x, int y, int z) {
	printf("? %d %d %d\n", x, y, z);
	fflush(stdout);
	int ans = -1;
	(void)scanf("%d", &ans);
	if (ans == -1) exit(0);
	return ans;
}

__attribute__((noreturn))
void guess(int x, int y, int z) {
	printf("! %d %d %d\n", x, y, z);
	exit(0);
}


int main() {
	int N, M, K, Q;
	(void)scanf("%d %d %d %d", &N, &M, &K, &Q);
    assert(M == 1 && K == 1);

    vector<int> cache(N+1);
    auto ask = [&](int x) {
        if (cache[x]) return cache[x];
        return cache[x] = query(x, 1, 1);
    };
    if (N == 1) {
        guess(1, 1, 1);
    }

    int l = 1, r = N;
    int e1=-1, e2=-1;
    if (ask(l) >= ask(l+1)) {
        guess(l, 1, 1);
    }
    if (ask(r-1) <= ask(r)) {
        guess(l, 1,1);
    }
    while (l < r-1) {
        int m = (l+r) / 2;
        int a = ask(m), b = ask(m+1);
        if (a == b) {
            e1 = m;
            e2 = m+1;
        }
        if (a >= b) {
            r = m;
        } else {
            l = m;
        }
    }
    if (l != 1 && (ask(l-1) <= ask(l) && ask(l) >= ask(l+1)))
        guess(l, 1, 1);
    if (r != N && (ask(r-1) <= ask(r) && ask(r) >= ask(r+1)))
        guess(r, 1, 1);
    if (ask(e1-1) <= ask(e1) && ask(e1) >= ask(e2))
        guess(e1, 1, 1);
    else guess(e2, 1, 1);
}

Compilation message (stderr)

worm.cpp: In function 'int query(int, int, int)':
worm.cpp:8:13: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |  (void)scanf("%d", &ans);
      |        ~~~~~^~~~~~~~~~~~
worm.cpp: In function 'int main()':
worm.cpp:22:13: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |  (void)scanf("%d %d %d %d", &N, &M, &K, &Q);
      |        ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 22
• Subtask 3: 0 / 12
• Subtask 4: 0 / 19
• Subtask 5: 0 / 14
• Subtask 6: 0 / 23