题解 | #坐标移动#
坐标移动
https://www.nowcoder.com/practice/119bcca3befb405fbe58abe9c532eb29
画出dfa(确定性有限自动机)即可
// https://www.nowcoder.com/practice/119bcca3befb405fbe58abe9c532eb29
#include <iostream>
using namespace std;
using ii = pair<int, int>;
using handle = void (*)(int);
const int maxn = 5 + 1e4;
handle accept[maxn];
int trans[maxn][128], tsiz; // t[u][x] = v: u --x--> v
ii dxs[128];
string s; // input
ii ans;
void accept5(int p) {
// a1;
ii dx = dxs[s[p - 2]];
int length = s[p - 1] - '0';
dx.first *= length, dx.second *= length;
ans.first += dx.first, ans.second += dx.second;
// cout << s.substr(p - 2, 2) << endl;
// printf("%d,%d\n", ans.first, ans.second);
}
void accept6(int p) {
// a11;
ii dx = dxs[s[p - 3]];
int length = 10 * (s[p - 2] - '0') + s[p - 1] - '0';
dx.first *= length, dx.second *= length;
ans.first += dx.first, ans.second += dx.second;
// cout << s.substr(p - 3, 3) << endl;
// printf("%d,%d\n", ans.first, ans.second);
}
void init() {
dxs['W'] = {0, 1};
dxs['S'] = {0, -1};
dxs['A'] = {-1, 0};
dxs['D'] = {1, 0};
trans[0][';'] = 1; // 0 是非法状态,即如果没有转移,那么会转移到这个节点
trans[1]['W'] = 2, trans[1]['A'] = 2, trans[1]['S'] = 2, trans[1]['D'] = 2;
trans[1][';'] = 1;
for (int i = '0'; i <= '9'; ++i) trans[2][i] = 3;
trans[2][';'] = 1;
for (int i = '0'; i <= '9'; ++i) trans[3][i] = 4;
trans[3][';'] = 5; // a1
trans[4][';'] = 6; // a11
trans[5]['W'] = 2, trans[5]['A'] = 2, trans[5]['S'] = 2, trans[5]['D'] = 2;
accept[5] = accept5; // 5 是接受状态
trans[6]['W'] = 2, trans[6]['A'] = 2, trans[6]['S'] = 2, trans[6]['D'] = 2;
accept[6] = accept6; // 6 是接受状态
}
int main() {
init();
cin >> s;
int u = 1;
for (int i = 0; i < s.size(); ++i) {
u = trans[u][s[i]];
// cout << u << " ";
if (accept[u] != nullptr) accept[u](i);
}
printf("%d,%d", ans.first, ans.second);
}

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