Finish 2010-11-17 12:00:00 UTC

small change 9.3

by Yi Cao

Status: Passed
Results: 4092 (cyc: 10, node: 1048)
CPU Time: 59.501
Score: 821.682
Submitted at: 2010-11-15 23:43:19 UTC
Scored at: 2010-11-15 23:44:48 UTC

Current Rank: 367th (Highest: 1st )
Based on: small change 9.2 (diff)
Basis for: small change 9.4 (diff)
Basis for: deadmau5 unhooked (diff)
Basis for: deadmau5 unhooked (diff)
...and 37 others.

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Code
function [thrustRow, thrustCol] = nickelfelpeter(chart, aIndex, bIndex, maxThrottle)

y_winds         = chart(:,:,1);
x_winds         = chart(:,:,2);
[ny,nx]         = size(x_winds);
ay              = rem(aIndex-1, ny) + 1;
ax              = (aIndex - ay)/ny  + 1;
by              = rem(bIndex-1, ny) + 1;
bx              = (bIndex - by)/ny  + 1;
x               = (1:nx);
y               = (1:ny)';
X               = x(ones(ny,1),:);
Y               = y(:,ones(nx,1));

dist_to_B       = ((X - bx).^2 + (Y - by).^2).^1.15;
dist_to_A       = ((X - ax).^2 + (Y - ay).^2).^1.155;

dist_to_B_w     = dist_to_B*1e-4;
dist_to_A_w     = dist_to_A*1e-4;

fuel            = 100*ones(ny,nx);
fuel(aIndex)    = 0;
xvel            = zeros(ny,nx);
yvel            = xvel;
checked         = xvel;
previous_stop   = xvel;
min_fuel        = 0;
cost_to_B = dist_to_B(aIndex);
cost_to_B_idx = aIndex;
zoon = nx*ny*[10 0.37 0.16];
ziter = [500 700 500];
sf = [0.31 0.19 0.25];

for i = 1:numel(zoon)
    
    SDB_tf = dist_to_B(:)<=zoon(i);
    SDB_idx = find(SDB_tf);
    
    SDBchecked = checked(SDB_tf);
    SDBfuel = fuel(SDB_tf);
    SDBdist_to_B_w = dist_to_B_w(SDB_tf);
    SDBdist_to_B = dist_to_B(SDB_tf);
    SDBxvel = xvel(SDB_tf);
    SDByvel = yvel(SDB_tf);
    SDBX = X(SDB_tf);
    SDBY = Y(SDB_tf);
    SDBprevious_stop = previous_stop(SDB_tf);
    SDBcost_to_B_idx = find(cost_to_B_idx==SDB_idx);
    
    slowdown = maxThrottle+SDBdist_to_B*sf(i);
    
    it = 0;
    
    while (  min_fuel <= cost_to_B  && ~all(SDBchecked) && it < ziter(i))
        it                      = it + 1;
        metrix                  = SDBfuel + SDBchecked + SDBdist_to_B_w;
        [dummy,i_p]             = min(metrix);
        i_p_full                = SDB_idx(i_p);
        min_fuel                = SDBfuel(i_p);
        i_y                     = rem(i_p_full - 1,ny) + 1;
        i_x                     = (i_p_full - i_y)/ny  + 1;
        i_y_winds               = y_winds(i_p_full);
        i_x_winds               = x_winds(i_p_full);
        i_vy                    = SDByvel(i_p) + i_y_winds;
        i_vx                    = SDBxvel(i_p) + i_x_winds;
        i_new_vy                = SDBY - i_y;
        i_new_vx                = SDBX - i_x;
        i_thrust                = abs(i_new_vx - i_vx) + abs(i_new_vy - i_vy);
        i_fuel                  = i_thrust + min_fuel;
        i_impr_tf               = (i_thrust <= maxThrottle) & (abs(i_new_vy+i_y_winds)+abs(i_new_vx+i_x_winds)<slowdown) & (i_fuel < SDBfuel);
        i_impr_idx              = find(i_impr_tf);
        i_fuel_impr             = i_fuel  (i_impr_idx) ;
        SDBxvel           (i_impr_idx) = i_new_vx(i_impr_idx);
        SDByvel           (i_impr_idx) = i_new_vy(i_impr_idx);
        SDBfuel           (i_impr_idx) = i_fuel_impr;
        SDBprevious_stop  (i_impr_idx) = i_p_full;
        if i_impr_tf(SDBcost_to_B_idx)
            [cost_to_B SDBcost_to_B_idx] = min(SDBfuel(:) + SDBdist_to_B(:));
        else
            [cost_to_B_new SDBcost_to_B_idx_new] = min(SDBfuel(i_impr_idx) ...
                + SDBdist_to_B(i_impr_idx));
            
            if cost_to_B_new<cost_to_B
                cost_to_B = cost_to_B_new;
                SDBcost_to_B_idx = i_impr_idx(SDBcost_to_B_idx_new);
            end
        end
        SDBchecked(i_impr_idx)     = 0; %false;
        SDBchecked(i_p)            = 100; %true;
    end
    
    fuel(SDB_tf) = SDBfuel;
    previous_stop(SDB_tf) = SDBprevious_stop;
    xvel(SDB_tf) = SDBxvel;
    yvel(SDB_tf) = SDByvel;
    
end

fuel                    = fuel + dist_to_B;
cost_to_A               = min(fuel(:) + dist_to_A(:));

checked(:)                 = 0;
return_previous_stop    = checked;

it                      = 0;
min_fuel                = 0;

while ( min_fuel < cost_to_A &&  ~all(checked(:)) && it < min(nx*ny,2000))
    
    it                  = it + 1;
    metrix              = fuel + checked + dist_to_A_w; %****
    [dummy,i_p]             = min(metrix(:)); %****
    min_fuel            = fuel(i_p); %****
    
    i_y                 = rem(i_p - 1,ny) + 1;
    i_x                 = (i_p - i_y)/ny  + 1;
    i_vy                = yvel(i_p) + y_winds(i_p);
    i_vx                = xvel(i_p) + x_winds(i_p);
    i_new_vy            = Y-i_y;
    i_new_vx            = X-i_x;
    i_thrust            = abs(i_new_vx - i_vx) + abs(i_new_vy - i_vy);
    i_fuel              = i_thrust + min_fuel;
    i_impr_tf           = i_thrust <= maxThrottle & i_fuel < fuel;
    i_impr_idx          = find(i_impr_tf);
    fuel                (i_impr_idx) = i_fuel(i_impr_idx);
    xvel                (i_impr_idx) = i_new_vx(i_impr_idx);
    yvel                (i_impr_idx) = i_new_vy(i_impr_idx);
    return_previous_stop(i_impr_idx) = i_p;
   
    [cost_to_A] = min(fuel(:) + dist_to_A(:));
    checked(i_impr_idx) = 0;
    checked(i_p)        = 100;
    
end

cost_to_A           = fuel + dist_to_A;
[dummy,min_fuel]        = min(cost_to_A(:));
indices             = zeros(nx*ny,1);
indices(1)          = min_fuel(1);
next_move           = return_previous_stop(indices(1));
k                   = 1;
[indices, k] = while_next_move(indices, k, next_move, return_previous_stop);
next_move           = previous_stop(indices(k));
[indices, k] = while_next_move(indices, k, next_move, previous_stop);
indices             = indices(k:-1:1);

ypos                = rem(indices - 1, ny) + 1;
xpos                = (indices - ypos)/ny + 1;
xw                  = x_winds(indices);
yw                  = y_winds(indices);

thrustCol           = diff([0; diff(xpos)]) - xw(1:end-1);
thrustRow           = diff([0; diff(ypos)]) - yw(1:end-1);

end

function [indices, k] = while_next_move(indices, k, next_move, previous_stop)

while(next_move)
    k               = k + 1;
    indices(k)      = next_move;
    next_move       = previous_stop(next_move);
end

end