| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 958206 | robertopino | Connect (CEOI06_connect) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#pragma GCC optimize("Ofast,unroll-loops,no-stack-protector")
#include <bits/stdc++.h>
using namespace std;
#define fore(i, l, r) for (auto i = (l) - ((l) > (r)); i != (r) - ((l) > (r)); i += 1 - 2 * ((l) > (r)))
#define sz(x) int(x.size())
#define all(x) begin(x), end(x)
#define f first
#define s second
#define pb push_back
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...)
#endif
using ld = long double;
using lli = long long;
using ii = pair<int, int>;
const int N = 20, M = 80;
int dp[M][N + 1][1 << N];
const int N_BITSET = 7;
template <class T>
bool umin(T& a, T b) {
return (a = min(a, b)) == b;
}
int main() {
cin.tie(0)->sync_with_stdio(0), cout.tie(0);
int n, m;
cin >> n >> m;
vector<string> board(n);
getline(cin, board[0]);
debug(n, m);
int foobar = 0;
fore (i, 0, n) {
getline(cin, board[i]);
assert(sz(board[i]) == m);
debug(board[i]);
fore (j, 0, m) {
foobar += board[i][j] == 'X';
}
}
foobar /= 2;
n /= 2, m /= 2;
debug(n, m);
int completeMask = (1 << m) - 1;
#define coord(x) (x * 2 + 1)
auto isAFigure = [&] (int r, int c) -> bool {
if (r < 0 || c < 0) {
debug("isAFigure: Coordinates out of range");
return false;
}
debug(r, c);
r = coord(r), c = coord(c);
debug(r, c, board[r][c]);
return board[r][c] == 'X';
};
auto blocked = [&] (int r1, int c1, int r2, int c2) -> bool {
debug(r1, c1, r2, c2);
if (r1 < 0 || c1 < 0 || r2 < 0 || c2 < 0) {
debug("blocked: Coordinates out of range");
return false;
}
r1 = coord(r1), c1 = coord(c1);
r2 = coord(r2), c2 = coord(c2);
bool thereIsAWall = false;
if (r1 == r2) { // hor
debug("horizontal");
if (c1 > c2) {
swap(c1, c2);
}
// assert(c1 + 2 == c2);
thereIsAWall = board[r1][c1 + 1] == '|';
} else { // ver
debug("vertical");
// assert(c1 == c2);
if (r1 > r2) {
swap(r1, r2);
}
// assert(r1 + 2 == r2);
thereIsAWall = board[r1 + 1][c1] == '-';
}
debug(r1, c1, r2, c2, thereIsAWall);
return thereIsAWall;
};
auto additionalCost = [&] (int r, int c, int mask) -> bool {
if ((~mask & (1 << c)) && isAFigure(r - 1, c)) {
return true;
}
return false;
};
auto verify = [&] (int r, int c, int mask) -> bool {
bool invalid = false;
if (r > 0) {
fore (ith, c, m) {
bool bit = mask & (1 << ith);
invalid |= bit & !isAFigure(r - 1, ith) & blocked(r - 1, ith, r, ith);
invalid |= !bit & isAFigure(r - 1, ith) & blocked(r - 1, ith, r, ith);
}
}
return invalid;
};
auto turnOffBit = [&] (int& mask, int ith) {
mask &= completeMask ^ (1 << ith);
};
auto turnOnBit = [&] (int& mask, int ith) {
mask |= (1 << ith);
};
auto canPlaceAConnection = [&] (int r, int c, int mask) -> bool {
if (mask & (1 << c)) {
return isAFigure(r - 1, c) ? true : false;
} else {
return isAFigure(r - 1, c) ? false : true;
}
};
auto createNewPair = [&] (int r, int c, int mask) {
debug("createNewPair");
int me = dp[r][c][mask];
if (canPlaceAConnection(r, c, mask)) { // create a new pair (a, b)
int a = c;
debug("place in a", a);
for (int b = c + 1; b < m; b++) {
if (blocked(r, b - 1, r, b) || !canPlaceAConnection(r, b, mask)) {
break;
}
debug("place in b", b);
// int newMask = mask | (1 << a) | (1 << b);
int newMask = mask;
turnOnBit(newMask, a);
turnOnBit(newMask, b);
int newC = b + 1;
int len = abs(a - b) + 1;
// int cost = me + (len * 2 - 1);
int cost = me + len;
bitset<N_BITSET> newMaskBitset(newMask);
debug(a, b, newMaskBitset, newC, len, cost);
umin(dp[r][newC][newMask], cost);
if (isAFigure(r, b)) {
break;
}
}
}
debug("");
debug("");
};
// auto bitIsActuallySet = [&] (int r, int ith, int mask) -> bool {
// if (mask & (1 << ith))
// return true;
// return isAFigure(r - 1, ith);
// };
auto bitIsActuallySet = [&] (int r, int c, int mask) -> bool {
if (mask & (1 << c))
return isAFigure(r - 1, c) == false;
return isAFigure(r - 1, c) == true;
};
auto continueAConnection = [&] (int r, int c, int mask) {
int me = dp[r][c][mask];
debug("continueAConnection");
// move next connection to c
int index = -1;
fore (ith, c, m) {
if (bitIsActuallySet(r, ith, mask)) {
index = ith;
break;
}
}
debug(index);
if (index != -1) {
debug("left");
for (int ith = index; ith >= c; ith--) {
if (ith != index && (blocked(r, ith, r, ith + 1) || bitIsActuallySet(r, ith, mask))) {
break;
}
// move connection from index to ith if possible
int newMask = mask;
debug(index, ith);
debug(newMask);
turnOffBit(newMask, index);
turnOnBit(newMask, ith);
debug(newMask);
bitset<N_BITSET> newMaskBitset(newMask);
int newC = max(ith, index) + 1;
int len = abs(index - ith) + 1;
// int cost = me + (len * 2 - 1) + 1 + additionalCost(r, index, mask);
int cost = me + len + additionalCost(r, index, mask);
debug(ith, newC, len, cost, newMaskBitset);
umin(dp[r][newC][newMask], cost);
if (isAFigure(r, ith)) {
break;
}
}
// right
debug("right");
if (!isAFigure(r, c)) {
for (int ith = index + 1; ith < m; ith++) {
if (bitIsActuallySet(r, ith, mask) || blocked(r, ith - 1, r, ith)) { // is blocked
break;
}
// move end from index to ith if possible
int newMask = mask;
turnOffBit(newMask, index);
turnOnBit(newMask, ith);
int newC = max(ith, index) + 1;
int len = abs(index - ith) + 1;
// int cost = me + (len * 2 - 1) + 1 + additionalCost(r, index, mask);
int cost = me + len + additionalCost(r, index, mask);
umin(dp[r][newC][newMask], cost);
if (isAFigure(r, ith)) {
break;
}
}
}
}
};
auto meetTwoConnections = [&] (int r, int c, int mask) {
int me = dp[r][c][mask];
debug("meetTwoConnections");
if (bitIsActuallySet(r, c, mask) && !isAFigure(r, c)) {
fore (ith, c + 1, m) {
if (isAFigure(r, ith) || blocked(r, ith - 1, r, ith)) {
break;
}
if (!bitIsActuallySet(r, ith, mask)) {
continue;
}
int a = c, b = ith;
int newC = ith + 1;
int newMask = mask;
turnOffBit(newMask, a);
turnOffBit(newMask, b);
bitset<N_BITSET> newMaskBitset(newMask);
int len = abs(a - b) + 1;
// int cost = me + (len * 2 - 1) + 2 + additionalCost(r, a, mask) + additionalCost(r, b, mask);
int cost = me + len + additionalCost(r, a, mask) + additionalCost(r, b, mask);;
debug(a, b, newC, newMaskBitset, me, len);
umin(dp[r][newC][newMask], cost);
break;
}
}
};
memset(dp, 63, sizeof(dp));
dp[0][0][0] = 0;
fore (r, 0, n) {
fore (c, 0, m + 1) {
fore (mask, 0, 1 << m) {
auto me = dp[r][c][mask];
bitset<N_BITSET> maskBitset(mask);
debug(r, c, mask, me);
if (c == m) {
debug("next row");
umin(dp[r + 1][0][mask], me);
continue;
}
bool invalid = verify(r, c, mask);
if (invalid) {
debug("invalid, cannot continue");
continue;
}
if (!bitIsActuallySet(r, c, mask)) {
debug("do nothing");
int newMask = mask;
turnOffBit(newMask, c);
umin(dp[r][c + 1][newMask], me);
}
createNewPair(r, c, mask);
continueAConnection(r, c, mask);
meetTwoConnections(r, c, mask);
debug("---------------------------------------------");
}
debug("");
}
debug("");
}
debug("");
int mask = 0;
fore (i, 0, m) {
if (isAFigure(n - 1, i))
mask |= 1 << i;
}
// int sol = dp[n][0][mask] - foobar;
int sol = (dp[n][0][mask] - foobar) * 2;
cout << sol << '\n';
return 0;
}
/* Please, check the following:
* int overflow, array bounds
* special cases (n=1?)
* do smth instead of nothing and stay organized
* write down your ideas
* DON'T get stuck on ONE APPROACH!
* ASK for HELP from your TEAMMATES
*/