Submission #1166532

#	Time	Username	Problem	Language	Result	Execution time	Memory
1166532		sleepntsheep	Pictionary (COCI18_pictionary)	C11	Compilation error	0 ms	0 KiB

pictionary

#include <stdio.h>

#define N 333333

int n, m, q, 
	dfn[N], dep[N], timer, pa[N], k, c[N][2], w[N], now, sz[N], hld[N], Pa[N];

int f(int x) {
	if (pa[x] == x)
		return x;
	return pa[x] = f(pa[x]);
}

void edge(int u, int v) {
	u = f(u), v = f(v);
	if (u == v) return;
	++k;
	w[k] = now;
	c[k][0] = u;
	c[k][1] = v;
	Pa[u] = Pa[v] = k;
	pa[u] = pa[v] = k;
}

int dfs(int u) {
	return ! u ? 0 : sz[u] = 1 + dfs(c[u][0]) + dfs(c[u][1]);;
}

void dfs2(int u, int hd) {
	if (! u) return;
	dep[u] = dep[Pa[u]] + 1;
	dfn[u] = ++timer;
	hld[u] = hd;
	int d = sz[c[u][1]] >= sz[c[u][0]];
	dfs2(c[u][d], hd);
	dfs2(c[u][!d], c[u][!d]);
}

int lca(int u, int v) {
	while (hld[u] != hld[v]) {
		if (dep[hld[u]] < dep[hld[v]])
			v = Pa[hld[v]];
		else
			u = Pa[hld[u]];
	}
	return dep[u] < dep[v] ? u : v;
}

int main() {
	for (int i = 0; i < N; ++i) {
		pa[i] = i;
		sz[i] = 1;
		Pa[i] = i;
	}

	scanf("%d%d%d", &n, &m, &q);
	k = n;

	for (int gc = m; gc >= 1; --gc) {
		++now;
		for (int j = gc; j + gc <= n; j += gc)
			edge(j, j + gc);
	}

	dfs(k);
	dfs2(k, k);

	for (int aa, bb, i = 0; i < q; ++i) {
		scanf("%d%d", &aa, &bb);
		printf("%d\n", w[lca(aa, bb)]);
	}

	return 0;
}

Compilation message (stderr)

pictionary.c: In function 'dfs':
pictionary.c:26:32: error: lvalue required as left operand of assignment
   26 |         return ! u ? 0 : sz[u] = 1 + dfs(c[u][0]) + dfs(c[u][1]);;
      |                                ^
pictionary.c: In function 'main':
pictionary.c:56:9: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |         scanf("%d%d%d", &n, &m, &q);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~
pictionary.c:69:17: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |                 scanf("%d%d", &aa, &bb);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~