oj.uz

Submission #43327

# Submission time Handle Problem Language Result Execution time Memory
43327 2018-03-13T15:02:44 Z nonocut Boat (APIO16_boat) C++14
9 / 100
 21 ms 744 KB 
#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define pb push_back
#define pii pair<int,int>
#define X first
#define Y second

const int maxn = 2e5 + 5;
const ll mod = 1e9 + 7;

int n;
int a[maxn], b[maxn];
vector<int> pos;
int sz;
pii itv[maxn];
ll dp[maxn], temp[maxn], sum[maxn];

ll add(ll x, ll y) {
    return ((x+y)%mod + mod)%mod;
}
ll mul(ll x, ll y) {
    return ((x*y)%mod + mod)%mod;
}
ll inv(ll a, ll b){
    return 1<a ? b - inv(b%a,a)*b/a : 1;
}

void show(int key) {
//    printf("show %d\n",key);
//    for(int i=1;i<=sz;i++) printf("---- [%d, %d] : %lld\n",itv[i].X,itv[i].Y,dp[i]);
}

void init() {
    pos.pb(0); pos.pb(2e9);
    for(int i=1;i<=n;i++) pos.pb(a[i]), pos.pb(b[i]);
    sort(pos.begin(),pos.end());
    pos.erase(unique(pos.begin(),pos.end()),pos.end());
    for(int i=0;i<pos.size()-1;i++) {
        itv[++sz] = {pos[i],pos[i]};
        if(pos[i]+1<=pos[i+1]-1) itv[++sz] = {pos[i]+1,pos[i+1]-1};
    }
    show(0);
}

ll solve() {
    dp[1] = 1;
    for(int cur=1;cur<=n;cur++) {
        for(int x=1;x<=sz;x++) {
            temp[x] = 0;
            sum[x] = add(sum[x-1], dp[x]);
            if(a[cur]<=itv[x].X && itv[x].Y<=b[cur]) {
                int len = itv[x].Y-itv[x].X+1;
//                for(int y=1;y<x;y++) temp[x] = add(temp[x], mul(len, dp[y]));
                temp[x] = add(temp[x], mul(len, sum[x-1]));
                temp[x] = add(temp[x], (mul(mul(len-1, inv(2,mod)), dp[x])));
            }
        }
        for(int x=1;x<=sz;x++) dp[x] = add(dp[x], temp[x]);
        show(cur);
    }
    ll ans = 0;
    for(int x=2;x<=sz;x++) ans = add(ans, dp[x]);
    return ans;
}

int main() {
    scanf("%d",&n);
    for(int i=1;i<=n;i++) scanf("%d%d",&a[i],&b[i]);
    init();
    printf("%lld",solve());
}

Compilation message

boat.cpp: In function 'void init()':
boat.cpp:40:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<pos.size()-1;i++) {
                  ^
boat.cpp: In function 'int main()':
boat.cpp:69:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
                   ^
boat.cpp:70:52: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i=1;i<=n;i++) scanf("%d%d",&a[i],&b[i]);
                                                    ^

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 380 KB Output is correct
2 Correct 10 ms 480 KB Output is correct
3 Correct 11 ms 552 KB Output is correct
4 Correct 10 ms 552 KB Output is correct
5 Correct 10 ms 656 KB Output is correct
6 Correct 10 ms 656 KB Output is correct
7 Correct 11 ms 656 KB Output is correct
8 Correct 12 ms 656 KB Output is correct
9 Correct 11 ms 684 KB Output is correct
10 Correct 11 ms 684 KB Output is correct
11 Correct 10 ms 684 KB Output is correct
12 Correct 11 ms 684 KB Output is correct
13 Correct 11 ms 684 KB Output is correct
14 Correct 11 ms 744 KB Output is correct
15 Correct 11 ms 744 KB Output is correct
16 Correct 3 ms 744 KB Output is correct
17 Correct 4 ms 744 KB Output is correct
18 Correct 3 ms 744 KB Output is correct
19 Correct 3 ms 744 KB Output is correct
20 Correct 3 ms 744 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 380 KB Output is correct
2 Correct 10 ms 480 KB Output is correct
3 Correct 11 ms 552 KB Output is correct
4 Correct 10 ms 552 KB Output is correct
5 Correct 10 ms 656 KB Output is correct
6 Correct 10 ms 656 KB Output is correct
7 Correct 11 ms 656 KB Output is correct
8 Correct 12 ms 656 KB Output is correct
9 Correct 11 ms 684 KB Output is correct
10 Correct 11 ms 684 KB Output is correct
11 Correct 10 ms 684 KB Output is correct
12 Correct 11 ms 684 KB Output is correct
13 Correct 11 ms 684 KB Output is correct
14 Correct 11 ms 744 KB Output is correct
15 Correct 11 ms 744 KB Output is correct
16 Correct 3 ms 744 KB Output is correct
17 Correct 4 ms 744 KB Output is correct
18 Correct 3 ms 744 KB Output is correct
19 Correct 3 ms 744 KB Output is correct
20 Correct 3 ms 744 KB Output is correct
21 Incorrect 21 ms 744 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 744 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 380 KB Output is correct
2 Correct 10 ms 480 KB Output is correct
3 Correct 11 ms 552 KB Output is correct
4 Correct 10 ms 552 KB Output is correct
5 Correct 10 ms 656 KB Output is correct
6 Correct 10 ms 656 KB Output is correct
7 Correct 11 ms 656 KB Output is correct
8 Correct 12 ms 656 KB Output is correct
9 Correct 11 ms 684 KB Output is correct
10 Correct 11 ms 684 KB Output is correct
11 Correct 10 ms 684 KB Output is correct
12 Correct 11 ms 684 KB Output is correct
13 Correct 11 ms 684 KB Output is correct
14 Correct 11 ms 744 KB Output is correct
15 Correct 11 ms 744 KB Output is correct
16 Correct 3 ms 744 KB Output is correct
17 Correct 4 ms 744 KB Output is correct
18 Correct 3 ms 744 KB Output is correct
19 Correct 3 ms 744 KB Output is correct
20 Correct 3 ms 744 KB Output is correct
21 Incorrect 21 ms 744 KB Output isn't correct
22 Halted 0 ms 0 KB -