Submission #50352

#	Time	Username	Problem	Language	Result	Execution time	Memory
50352		duality	Boat (APIO16_boat)	C++11	100 / 100	877 ms	5256 KiB

boat

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

// basic debugging macros
int __i__,__j__;
#define printLine(l) for(__i__=0;__i__<l;__i__++){cout<<"-";}cout<<endl
#define printLine2(l,c) for(__i__=0;__i__<l;__i__++){cout<<c;}cout<<endl
#define printVar(n) cout<<#n<<": "<<n<<endl
#define printArr(a,l) cout<<#a<<": ";for(__i__=0;__i__<l;__i__++){cout<<a[__i__]<<" ";}cout<<endl
#define print2dArr(a,r,c) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<a[__i__][__j__]<<" ";}cout<<endl;}
#define print2dArr2(a,r,c,l) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<setw(l)<<setfill(' ')<<a[__i__][__j__]<<" ";}cout<<endl;}

// advanced debugging class
// debug 1,2,'A',"test";
class _Debug {
    public:
        template<typename T>
        _Debug& operator,(T val) {
            cout << val << endl;
            return *this;
        }
};
#define debug _Debug(),

// define
#define MAX_VAL 999999999
#define MAX_VAL_2 999999999999999999LL
#define EPS 1e-6

// typedef
typedef unsigned int UI;
typedef long long int LLI;
typedef unsigned long long int ULLI;
typedef unsigned short int US;
typedef pair<int,int> pii;
typedef pair<LLI,LLI> plli;
typedef vector<int> vi;
typedef vector<LLI> vlli;
typedef vector<pii> vpii;
typedef vector<plli> vplli;

// ---------- END OF TEMPLATE ----------
#define MOD 1000000007

int a[500],b[500];
vi l;
LLI inv[501];
LLI dp[500][1000];
int main() {
    int i;
    int N;
    scanf("%d",&N);
    for (i = 0; i < N; i++) scanf("%d %d",&a[i],&b[i]),b[i]++,l.push_back(a[i]),l.push_back(b[i]);
    l.push_back(-1);
    sort(l.begin(),l.end());
    l.resize(unique(l.begin(),l.end())-l.begin());

    int j,k;
    int s = 0,x;
    LLI w;
    for (i = 1; i <= N; i++) {
        int e = MOD-2;
        LLI r = 1,b = i;
        while (e > 0) {
            if (e & 1) r *= b,r %= MOD;
            e >>= 1;
            b *= b,b %= MOD;
        }
        inv[i] = r;
    }
    for (i = 0; i < N; i++) {
        for (j = 1; j < (l.size()-1); j++) {
            w = 1,x = 0;
            dp[i][j] = dp[i][j-1];
            for (k = i; k >= 0; k--) {
                if ((l[j] >= a[k]) && (l[j+1] <= b[k])) {
                    w *= l[j+1]-l[j]+x,w %= MOD;
                    w *= inv[x+1],w %= MOD;
                    x++;
                }
                else if (k == i) break;
                if (k == 0) dp[i][j] += w;
                else dp[i][j] += w*dp[k-1][j-1];
                dp[i][j] %= MOD;
            }
        }
        s += dp[i][l.size()-2],s %= MOD;
    }
    printf("%d\n",s);

    return 0;
}

Compilation message (stderr)

boat.cpp: In function 'int main()':
boat.cpp:72:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (j = 1; j < (l.size()-1); j++) {
                     ~~^~~~~~~~~~~~~~
boat.cpp:52:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&N);
     ~~~~~^~~~~~~~~
boat.cpp:53:80: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for (i = 0; i < N; i++) scanf("%d %d",&a[i],&b[i]),b[i]++,l.push_back(a[i]),l.push_back(b[i]);
                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 22 / 22
• Subtask 3: 27 / 27
• Subtask 4: 42 / 42