Submission #172325

#	Time	Username	Problem	Language	Result	Execution time	Memory
172325		ho94949	Abduction 2 (JOI17_abduction2)	C++17	44 / 100	454 ms	35576 KiB

abduction2

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

enum {UP, LEFT, DOWN, RIGHT};
const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, -1, 0, 1};
const int MAXN = 65536;
const int lgMAXN = 16;
int H, W, Q;
int A[MAXN], B[MAXN];

//Am[i][j]: max of [i, i+2^j)
int Am[MAXN][lgMAXN], Bm[MAXN][lgMAXN];

int lg(int a)
{
    return 31 - __builtin_clz(a);
}

void spinit()
{
    for(int i=0; i<H; ++i) Am[i][0] = A[i];
    for(int i=0; i<W; ++i) Bm[i][0] = B[i];
    for(int j=1; j<lgMAXN; ++j)
    {
        for(int i=0; i<=H-(1<<j); ++i)
            Am[i][j] = max(Am[i][j-1], Am[i+(1<<(j-1))][j-1]);
        for(int i=0; i<=W-(1<<j); ++i)
            Bm[i][j] = max(Bm[i][j-1], Bm[i+(1<<(j-1))][j-1]);
    }
}

int MA(int s, int e)
{
    int q = lg(e-s+1);
    return max(Am[s][q], Am[e+1-(1<<q)][q]);
}
int MB(int s, int e)
{
    int q = lg(e-s+1);
    return max(Bm[s][q], Bm[e+1-(1<<q)][q]);
}


bool ins(int x, int y){ return 0<=x&&x<H&&0<=y&&y<W; }
map<tuple<int, int, int>, int > M;
int solve(int x, int y, int d)
{
    auto it = M.find(make_tuple(x, y, d));
    if(it != M.end()) return it->second;
    if(d==UP)
    {
        int lo = -1; //pos
        int hi = x; //imp
        while(lo+1!=hi)
        {
            int mi  = (lo+hi)>>1;
            if(MA(mi, x-1) > B[y]) lo = mi;
            else hi = mi;
        }
        //printf("%d %d UP -> %d %d\n", x, y, lo, y);
        if(lo==-1) return M[{x, y, d}] = x;
        else return M[{x, y, d}] = (x-lo) +
            max(solve(lo, y, LEFT), solve(lo, y, RIGHT));
    }
    if(d==DOWN)
    {
        int lo = x; //imp
        int hi = H; //pos
        while(lo+1!=hi)
        {
            int mi = (lo+hi)>>1;
            if(MA(x+1, mi) > B[y]) hi = mi;
            else lo = mi;
        }
        //printf("%d %d DOWN -> %d %d\n", x, y, hi, y);
        if(hi == H) return M[{x, y, d}] = H-1-x;
        else return M[{x, y, d}] = (hi-x) +
            max(solve(hi, y, LEFT), solve(hi, y, RIGHT));
    }
    if(d==LEFT)
    {
        int lo = -1; //pos
        int hi = y; //imp
        while(lo+1!=hi)
        {
            int mi = (lo+hi)>>1;
            if(MB(mi, y-1) > A[x]) lo = mi;
            else hi = mi;
        }
        //printf("%d %d LEFT -> %d %d\n", x, y, x, lo);
        if(lo == -1) return M[{x, y, d}] = y;
        else return M[{x, y, d}] = (y-lo) +
            max(solve(x, lo, UP), solve(x, lo, DOWN));
    }
    if(d==RIGHT)
    {
        //puts("HELLO!");
        int lo = y; //imp
        int hi = W; //pos
        while(lo+1!=hi)
        {
            int mi = (lo+hi)>>1;
            if(MB(y+1, mi) > A[x]) hi = mi;
            else lo = mi;
        }
        //printf("%d %d RIGHT -> %d %d\n", x, y, x, hi);
        //puts("BYE!");
        if(hi == W) return M[{x, y, d}] = W-1-y;
        else return M[{x, y, d}] = (hi-y) +
            max(solve(x, hi, UP), solve(x, hi, DOWN));
    }
}
int main()
{
    scanf("%d%d%d", &H, &W, &Q);
    for(int i=0; i<H; ++i)
        scanf("%d", A+i);
    for(int i=0; i<W; ++i)
        scanf("%d", B+i);
    spinit();
    while(Q--)
    {
        int S, T; scanf("%d%d", &S, &T); --S; --T;
        int ans = 0;
        for(int d=0; d<4; ++d)
            ans = max(ans, solve(S, T, d));
        printf("%d\n", ans);
    }
}

Compilation message (stderr)

abduction2.cpp: In function 'int solve(int, int, int)':
abduction2.cpp:113:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
abduction2.cpp: In function 'int main()':
abduction2.cpp:116:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d%d", &H, &W, &Q);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~
abduction2.cpp:118:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", A+i);
         ~~~~~^~~~~~~~~~~
abduction2.cpp:120:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", B+i);
         ~~~~~^~~~~~~~~~~
abduction2.cpp:124:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         int S, T; scanf("%d%d", &S, &T); --S; --T;
                   ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 10 / 10
• Subtask 3: 17 / 17
• Subtask 4: 4 / 4
• Subtask 5: 0 / 56