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답안 #386508

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
386508 2021-04-06T16:57:15 Z kostia244 Islands (IOI08_islands) C++17
100 / 100
 475 ms 74732 KB 
#include<stdio.h>
#include<bitset>
#define next uwuwuwuwu
using namespace std;
using ll = long long;
const int maxn = 1e6 + 6;
const ll inf = (1ll<<50);
int n;
int up[maxn];
ll dp[maxn];
int tmp[maxn], tmp2[maxn], sz = 0, offset = 0, tsz = 0;
bitset<maxn> vis;
 
int link[maxn], next[maxn];
__attribute__(( always_inline)) inline void add_edge(int v, int ch) {
    next[ch] = link[v];
    link[v] = ch;
}
 
ll ans;
 
void dfs(int v) {
    #define u link[v]
    for(dp[v] = 0; u; u = next[u]) {
        dfs(u);
        ans = max(ans, dp[v] + dp[u] + up[u]);
        dp[v] = max(dp[v], dp[u] + up[u]);
    }
    #undef u
}
 
int main() {
    //cin.tie(0)->sync_with_stdio(0);
    scanf("%d", &n);
    for(int i = 1; i <= n; i++) {
        scanf("%d%lld", &up[i], &dp[i]);
    }
    for(int i = 1; i <= n; i++) if(!vis[i]) {
        sz = offset;
        int v = i;
        while(!vis[v]) {
            tmp[sz] = v;
            tmp2[sz++] = dp[v];
            vis[v] = 1;
            v = up[v];
        }
        for(int i = 0; offset+i < sz-i-1; i++) {
            swap(tmp[offset+i], tmp[sz-1-i]);
            swap(tmp2[offset+i], tmp2[sz-1-i]);
        }
        while(sz>offset && tmp[sz-1] != v) sz--;
        for(int i = offset+1; i < sz; i++)
            swap(tmp2[i], tmp2[i-1]);
        if(sz<=offset) continue;//no new cycle
        tmp2[sz-1] *= -1;
        offset = sz;
    }
    vis = 0;
    for(int i = 0; i < sz; i++)
        vis[tmp[i]] = 1;
    for(int i = 1; i <= n; i++) if(!vis[i]) {
        add_edge(up[i], i);
    }
    for(int i = 0; i <= n; i++)
        up[i] = dp[i];
    ll totalAns = 0, total = 0, pref = 0, A = -inf, B = -inf;
    for(int start = 0, end = 0; start < sz; start = ++end) {
        total = 0, pref = 0, A = -inf, B = -inf, ans = -inf;
        while(tmp2[end] >= 0) {
            total += tmp2[end];
            end++;
        }
        for(int i = start; i <= end; i++) {
            dfs(tmp[i]);
            ans = max(ans, A + pref + dp[tmp[i]]);
            ans = max(ans, B + dp[tmp[i]] + (total-pref) - tmp2[end]);
            A = max(A, dp[tmp[i]]-pref);
            B = max(B, dp[tmp[i]]+pref);
            pref += tmp2[i];
        }
        totalAns += ans;
    }
    printf("%lld", totalAns);
}

Compilation message

islands.cpp: In function 'int main()':
islands.cpp:34:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   34 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
islands.cpp:36:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   36 |         scanf("%d%lld", &up[i], &dp[i]);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
33.0 / 33.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 620 KB Output is correct
2 Correct 1 ms 620 KB Output is correct
3 Correct 1 ms 620 KB Output is correct
4 Correct 1 ms 620 KB Output is correct
5 Correct 1 ms 620 KB Output is correct
6 Correct 1 ms 620 KB Output is correct
7 Correct 1 ms 620 KB Output is correct
8 Correct 1 ms 620 KB Output is correct
9 Correct 1 ms 620 KB Output is correct
10 Correct 1 ms 620 KB Output is correct
11 Correct 1 ms 640 KB Output is correct

Subtask #2
3.0 / 3.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 620 KB Output is correct
2 Correct 1 ms 620 KB Output is correct

Subtask #3
4.0 / 4.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 640 KB Output is correct
2 Correct 2 ms 620 KB Output is correct

Subtask #4
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 876 KB Output is correct
2 Correct 11 ms 1388 KB Output is correct
3 Correct 7 ms 1004 KB Output is correct
4 Correct 4 ms 748 KB Output is correct

Subtask #5
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 14 ms 1772 KB Output is correct
2 Correct 26 ms 2796 KB Output is correct

Subtask #6
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 53 ms 4716 KB Output is correct
2 Correct 54 ms 5100 KB Output is correct
3 Correct 71 ms 6636 KB Output is correct

Subtask #7
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 104 ms 9196 KB Output is correct
2 Correct 122 ms 11884 KB Output is correct
3 Correct 144 ms 12396 KB Output is correct
4 Correct 185 ms 16236 KB Output is correct

Subtask #8
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 264 ms 16236 KB Output is correct
2 Correct 299 ms 20204 KB Output is correct
3 Correct 205 ms 18284 KB Output is correct
4 Correct 253 ms 23276 KB Output is correct
5 Correct 248 ms 23332 KB Output is correct
6 Correct 475 ms 19436 KB Output is correct
7 Correct 285 ms 24684 KB Output is correct

Subtask #9
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 304 ms 74732 KB Output is correct
2 Correct 292 ms 43756 KB Output is correct
3 Correct 266 ms 20076 KB Output is correct
4 Correct 317 ms 20076 KB Output is correct
5 Correct 260 ms 23660 KB Output is correct
6 Correct 261 ms 20972 KB Output is correct
7 Correct 415 ms 19820 KB Output is correct