UVA-1589 象棋 题解答案代码 算法竞赛入门经典第二版

​​https://github.com/jzplp/aoapc-UVA-Answer​​

#include<cstdio>
#include<vector>
using namespace std;

int black_x, black_y;
int x,y;
struct point {
  char c;
  int x, y;
};
vector<point> v;

int sx[4] = {1,0,-1,0};
int sy[4] = {0,1,0,-1};

bool flyBlackGeneral() {
  int i, j;
  for(i=0; i<v.size(); ++i)
    if(v[i].c == 'G') {
      if(black_y == v[i].y) {
        j = i;
        break;
      } else
        return false;
    }
  for(i=0; i<v.size(); ++i) {
    if(i == j)
      continue;
    if(black_y == v[i].y && v[i].x > black_x && v[i].x < v[j].x)
      return false;
  }
  return true;
}

bool flyRedGeneral(int i) {
  int j;
  if(y != v[i].y)
    return false;
  for(j=0; j<v.size(); ++j) {
    if(i == j)
      continue;
    if(y == v[j].y && v[j].x > x && v[j].x < v[i].x)
      return false;
  }
  return true;
}

bool chaript(int i) {
  int j, beg, end;
  if(x != v[i].x && y != v[i].y)
    return false;
  if(x == v[i].x) {
    beg = (y > v[i].y) ? v[i].y : y;
    end = (y > v[i].y) ? y : v[i].y;
  }
  if(y == v[i].y) {
    beg = (x > v[i].x) ? v[i].x : x;
    end = (x > v[i].x) ? x : v[i].x;
  }
  for(j=0; j<v.size(); ++j) {
    if(i == j)
      continue;
    if(x == v[j].x && v[j].y > beg && v[j].y < end)
      return false;
    if(y == v[j].y && v[j].x > beg && v[j].x < end)
      return false;
  }
  return true;
}

int hx[8] = {-2,-2,1,-1, 2,2, 1,-1};
int hy[8] = { 1,-1,2, 2,-1,1,-2,-2};
int hxx[4] = {-1,0,1, 0};
int hyy[4] = { 0,1,0,-1};

bool horse(int i) {
  int j,k,hox,hoy,hoxx,hoyy;
  for(j=0; j<8; ++j) {
    hox = v[i].x + hx[j];
    hoy = v[i].y + hy[j];
    if(x != hox || y != hoy)
      continue;
    hoxx = v[i].x + hxx[j/2];
    hoyy = v[i].y + hyy[j/2];
    for(k=0; k<v.size(); ++k) {
      if(k == i)
        continue;
      if(hoxx == v[k].x && hoyy == v[k].y)
        break;
    }
    if(k != v.size())
      continue;
    return true;
  }
  return false;
}

bool cannon(int i) {
  int j, beg, end, k=0;
  if(x != v[i].x && y != v[i].y)
    return false;
  if(x == v[i].x) {
    beg = (y > v[i].y) ? v[i].y : y;
    end = (y > v[i].y) ? y : v[i].y;
  }
  if(y == v[i].y) {
    beg = (x > v[i].x) ? v[i].x : x;
    end = (x > v[i].x) ? x : v[i].x;
  }
  for(j=0; j<v.size(); ++j) {
    if(i == j)
      continue;
    if(x == v[j].x && v[j].y > beg && v[j].y < end)
      ++k;
    if(y == v[j].y && v[j].x > beg && v[j].x < end)
      ++k;
  }
  if(k == 1)
    return true;
  return false;
}

int main() {
  int n,i,j;
  point p, ptemp;
  int flag;
  bool eat;
  while(scanf("%d %d %d", &n, &black_x, &black_y) == 3 && n != 0) {
    v.clear();
    for(i=0; i!=n; ++i) {
      scanf(" %c %d %d", &p.c, &p.x, &p.y);
      v.push_back(p);
    }
    if(flyBlackGeneral() == true) {
      puts("NO");
      continue;
    }
    for(i=0; i<4; ++i) {
      x = black_x + sx[i];
      y = black_y + sy[i];
      if(x < 1 || x > 3 || y < 4 || y > 6)
        continue;
      eat = false;
      for(j=0;j<v.size();++j)
        if(x == v[j].x && y == v[j].y) {
          ptemp = v[j];
          v.erase(v.begin()+j);
          eat = true;
          break;
        }
      flag = 0;
      for(j=0; j<v.size(); ++j)
        switch(v[j].c) {
          case 'G':
            flag += flyRedGeneral(j);
            break;
          case 'R':
            flag += chaript(j);
            break;
          case 'H':
            flag += horse(j);
            break;
          case 'C':
            flag += cannon(j);
            break;
        }
      if(flag == 0)
        break;
      if(eat == true) {
        v.push_back(ptemp);
      }
    }
    if(flag == 0)
      puts("NO");
    else
      puts("YES");
  }
  return 0;
}