oj.uz

답안 #1036144

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1036144 2024-07-27T04:12:22 Z sleepntsheep Islands (IOI08_islands) C
48 / 100
 221 ms 127792 KB 
#include <stdio.h>

#define NN 1000001
#define MM 2000002

long long max(long long i, long long j) {return i > j ? i : j;} 

int n, ww[MM], to[MM], lnk[MM], head[NN], col[NN];

void link(int u, int v, int w) {
    static int ii = 0;
    int i = ++ii;
    to[i] = v;
    ww[i] = w;
    lnk[i] = head[u];
    head[u] = i;
}

int cycle_head, cycle_tail;
int cyc[NN], co, par[NN], incyc[NN];
long long tentacle[NN], aa[NN];

int dfs(int u, int p) {
    par[u] = p;
    col[u] = 1;

    for (int j = head[u]; j; j = lnk[j]) {
        int v = to[j];
        if (v == p) continue;
        if (col[v]) {
            cycle_head = u;
            cycle_tail = v;

            co = 0;
            cyc[co++] = v;
            int cur = u;
            for (; cur != v && cur != -1; cur = par[cur])
                cyc[co++] = cur;

            return 1;
        }
        if (dfs(v, u))
            return 1;
    }
    return 0;
}

void dfs2(int u, int p) {
    col[u] = 1;
    for (int j = head[u]; j; j = lnk[j]) {
        int v = to[j];
        if (v == p || incyc[v]) continue;
        dfs2(v, u);
        if (tentacle[v] + ww[j] > tentacle[u])
            tentacle[u] = tentacle[v] + ww[j];
    }
}

long long answer = 0;

int main() {
    scanf("%d", &n);
    for (int i = 1, j, k; i <= n; ++i)
        scanf("%d%d", &j, &k), link(i, j, k), link(j, i, k);

    for (int ii = 1; ii <= n; ++ii) {
        if (col[ii]) continue;

        dfs(ii, -1);

        long long op0 = -1e18, op1 = -1e18, here = 0;

        if (co == 2) {
            for (int j = head[cycle_head]; j; j = lnk[j])
                if (cycle_tail == to[j])
                    here = max(here, ww[j]);
            answer += here;
            continue;
        }

        for (int i = 0; i < co; ++i) incyc[cyc[i]] = 1;
        long long cycle_w = 0;
        for (int i = 0; i < co; ++i) {
            for (int j = head[cyc[i]]; j; j = lnk[j])
                if (incyc[to[j]]) cycle_w += ww[j];
            dfs2(cyc[i], -1);
        }
        cycle_w /= 2;

        for (int i = 0; i < co; ++i) {
            here = max(here, tentacle[cyc[i]] + max(aa[i] + op0, -aa[i] + op1));

            op0 = max(tentacle[cyc[i]] - aa[i], op0);
            op1 = max(tentacle[cyc[i]] + cycle_w + aa[i], op1);

            if (i + 1 < co)
                for (int j = head[cyc[i]]; j; j = lnk[j])
                    if (to[j] == cyc[i + 1]) {
                        aa[i + 1] = aa[i] + ww[j];
                        break;
                    }
        }

        answer += here;
    }
    printf("%lld\n", answer);
}

Compilation message

islands.c: In function 'main':
islands.c:62:5: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   62 |     scanf("%d", &n);
      |     ^~~~~~~~~~~~~~~
islands.c:64:9: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |         scanf("%d%d", &j, &k), link(i, j, k), link(j, i, k);
      |         ^~~~~~~~~~~~~~~~~~~~~

Subtask #1
15.0 / 33.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 344 KB Output is correct
2 Incorrect 0 ms 348 KB Output isn't correct
3 Correct 0 ms 348 KB Output is correct
4 Incorrect 1 ms 348 KB Output isn't correct
5 Correct 0 ms 348 KB Output is correct
6 Incorrect 0 ms 348 KB Output isn't correct
7 Incorrect 0 ms 348 KB Output isn't correct
8 Correct 0 ms 348 KB Output is correct
9 Incorrect 0 ms 348 KB Output isn't correct
10 Incorrect 0 ms 348 KB Output isn't correct
11 Correct 0 ms 348 KB Output is correct

Subtask #2
3.0 / 3.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 1 ms 604 KB Output is correct

Subtask #3
0 / 4.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 1 ms 600 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 1372 KB Output is correct
2 Correct 9 ms 3420 KB Output is correct
3 Incorrect 4 ms 1628 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #5
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 4952 KB Output is correct
2 Correct 20 ms 7260 KB Output is correct

Subtask #6
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 44 ms 13652 KB Output is correct
2 Correct 42 ms 17516 KB Output is correct
3 Correct 49 ms 26904 KB Output is correct

Subtask #7
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 62 ms 24892 KB Output is correct
2 Correct 94 ms 44368 KB Output is correct
3 Correct 121 ms 48968 KB Output is correct
4 Correct 127 ms 68432 KB Output is correct

Subtask #8
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 143 ms 47960 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 221 ms 127792 KB Output isn't correct
2 Halted 0 ms 0 KB -